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  • 1990-1994  (5,181)
  • 1970-1974
  • 1925-1929
  • 1890-1899  (1,702)
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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Amino acids 1 (1991), S. 225-237 
    ISSN: 1438-2199
    Keywords: Amino acids ; Catalepsy ; Movement initiation ; NMDA antagonists ; Glycine ; Parkinson's disease ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The anticataleptic effects of non-competitive and competitive NMDA antagonists as well as those of an agonist at the allosteric glycine binding site of the NMDA receptor were tested in the catalepsy model. Some of these drugs were further tested in a reaction time task demanding rapid locomotor initiation. The results show that the non-competitive NMDA antagonists dizocilpine and memantine as well as the competitive antagonists CGP 39551, CGP 37849 and CPPene antagonized dopamine D2 receptor mediated catalepsy induced by haloperidol. D-cycloserine, a partial glycine agonist per se had no effects, but it enhanced the anticataleptic effects of dizocilpine when coadministered. However, the effects of CGP 37849 were abolished. Dopamine D1 receptor mediated catalepsy induced by SCH 23390 was antagonized by dizocilpine, memantine, CPPene, but not by CGP 37849. In the reaction time task dizocilpine, memantine and CGP 37849 were tested for their anti-akinetic and anti-bradykinetic potencies. All these compounds improved haloperidolinduced slowing of reaction time. However, they acted differentially on haloperidol-induced slowing of movement execution and decreased initial acceleration. Thus, antagonists at the NMDA receptor may have a therapeutic potential in the treatment of Parkinson's disease. Their potency can be manipulated specifically at the glycine binding site.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    International journal of legal medicine 104 (1991), S. 185-188 
    ISSN: 1437-1596
    Keywords: Diazepam ; Radioimmunoassay ; Rat ; Bone marrow ; Serum ; Saliva ; Diazepam ; Radioimmunoassay ; Ratte ; Knochenmark ; Serum ; Speichel
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine , Law
    Description / Table of Contents: Zusammenfassung 1, 2, 4 und 8 Stunden nach intraperitonealer Injektion wurde die Verteilung von Diazepam in Körperflüssigkeiten und Geweben von Ratten untersucht. Die Untersuchung erfolgte mit Hilfe eines Radioimmunoassays und mit einem spezifischen Antidiazepam-Antikörper. Die Diazepamspiegel im Serum, im Speichel, im Gehirn und im Knochenmark fielen über eine Zeitdauer von 2 Stunden ab und zeigten nach 4 Stunden eine Nivellierung. Die Diazepamkonzentration im Knochenmark war viel höher als im Serum, im Speichel und im Gehirn. Dieser Befund muß an eine Akkumulation von Diazepam in diesem Gewebe denken lassen. Dieser Befund weist auch darauf hin, daß Knochenmark ein nützliches Material für den Nachweis von Diazepam bei skeletierten überbleibseln sein kann. Die Diazepamkonzentrationen im Knochenmark, im Serum, im Speichel und im Hirngewebe zeigten eine lineare Korrelation (r = 0.860–0.997). Dieser Befund weist dar auf hin, daß eine zuverlässige Abschätzung der Diazepamkonzentration im Blut aufgrund der Befunde im Knochenmark erfolgen kann.
    Notes: Summary The distribution of diazepam in biological fluids and tissues of rats was examined 1, 2, 4 and 8 h after intraperitoneal administration by using a radioimmunoassay with specific anti-diazepam antibody. The diazepam levels in serum, saliva, brain and bone marrow decreased over a period of 2h and levelled off 4h after administration. The diazepam concentration in bone marrow was much higher than in serum, saliva and brain, suggesting an accumulation of diazepam in this tissue. This indicates that bone marrow could be a very useful material for the detection of diazepam in skeletonized remains. The diazepam concentrations in bone marrow, serum, saliva and brain showed a linear relationship (r = 0.860–0.997), indicating that a valid estimate of diazepam concentration in blood can be made from bone marrow samples.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    International journal of legal medicine 104 (1991), S. 93-97 
    ISSN: 1437-1596
    Keywords: Diethylene glycol ; Intoxication ; Myocardium ; Myocytolysis ; Ultrastructure ; Mitochondria ; Guinea pig ; Diethylenglycol ; Intoxikation ; Myokard ; Myozytolyse ; Ultrastruktur ; Mitochondrien ; Meerschweinchen
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine , Law
    Description / Table of Contents: Zusammenfassung Das Myokard von Meerschweinchen, welche mit subletalen Mengen von Diethylenglycol über eine Zeitdauer von 2–11 Tagen gefüttert worden waren, wurde mikroskopisch und elektronenmikroskopisch untersucht. Eine Koagulationsmyozytolyse und Verlust von Myofibrillen war fleckförmig verstreut über das Myokard. Diese Veränderungen waren in den Kontrollen nicht zu beobachten. Die begleitenden ultrastrukturellen Veränderungen bestanden in Schwellung, Pleomorphie, Hyperplasie von Mitochondrien, begleitet von einer Erweiterung der interfibrillären Räume und Verlagerung, Verzerrung und Ruptur angrenzender Fibrillen.
    Notes: Summary The myocardium of guinea pigs fed on sublethal doses of diethylene glycol (DEG) over a period of 2–11 days was examined for microscopical and ultrastructural changes. Coagulative myocytolysis and loss of myofibrils, not observed in the controls, was patchily distributed throughout the myocardium. The accompanying ultrastructural features included swelling, pleomorphism and hyperplasia of mitochondria with an associated distension of the interfibrillary spaces and a displacement, distortion and rupture of adjacent myofibrils.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Journal of molecular medicine 69 (1991), S. 1095-1098 
    ISSN: 1432-1440
    Keywords: Liver ; Warm ischemia ; Reperfusion ; Oxygen radicals ; Allopurinol ; Deferoxamine ; Iron ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The generation of free oxygen radicals is presumed as a substantial pathogenetic principle in reperfusion injury. Although demonstrated in gut, muscle and kidneys its role in liver reperfusion injury is still under investigation. In an experimental rat model of warm liver ischemia of 60 min and 8 h reperfusion electron resonance spectroscopy assessed the increased generation of free radicals in early reperfusion period, leading to a decrease of polyunsaturated free fatty acids in liver tissue within 15 min of reperfusion. Histologically, single cell death, local and patchy necrosis of hepatic lobuli could be observed after 8 h reperfusion (n=6). These histologic signs of liver injury could be attenuated by administration of superoxid-dismutase in combination with catalase but not by allopurinol. Best results could be obtained by deferoxamine. This indicates that increased generation of free oxygen radicals in reperfusion is not caused by the known conversion of xanthine-dehygrogenase to -oxidase but is mediated by an increased generation of hydroxyl-radicals, which can be scavenged by deferoxamine.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Naunyn-Schmiedeberg's archives of pharmacology 343 (1991), S. 46-51 
    ISSN: 1432-1912
    Keywords: Aortic baroreceptor reflex ; Excitatory amino acid receptors ; Caudal ventrolateral medulla ; Kynurenate ; Muscimol ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The caudal ventrolateral medulla (CVLM) contains vasodepressor neurons which, when activated, decrease vasomotor tone. To investigate whether excitatory amino acid receptors in the CVLM of the rat are involved in mediation of the aortic baroreceptor reflex, we microinjected amino acid antagonists unilaterally into the CVLM and examined their effects on the depressor response to electrical stimulation of the aortic nerve which contains mainly baroreceptor afferent fibers in rats. Male Wistar rats were anaesthetized with urethane, paralyzed and artificially ventilated. To block reflex vagal effects, methylatropine (1 mg/kg) was given intravenously. Kynurenate (227 ng), an excitatory amino acid antagonist, injected ipsilaterally but not contralaterally into the CVLM markedly inhibited the depressor response to aortic nerve stimulation, while both injections produced a similar small increase in basal blood pressure. Muscimol (1 ng), a GABA receptor agonist, injected ipsilaterally into the CVLM partly inhibited the baroreflex response, while it produced a moderate increase in basal blood pressure. 2-Amino-5-phosphonovalerate (APV) (10 ng), a N-methyl-d-aspartate (NMDA) receptor antagonist, and MK-801 (30 ng), a NMDA receptor channel blocker, partly inhibited the baroreflex response. MK-801 (30 ng) injected into the CVLM reduced the depressor response to the NMDA receptor agonist NMDA (0.3 ng) but not to the quisqualate receptor agonist quisqualate (0.1 ng) and the kainate receptor agonist kainate (0.1 ng), while kynurenate (227 ng) inhibited the depressor response to all three excitatory amino acid receptor agonists. These findings provide further evidence for the presence of excitatory amino acid receptors involved in mediating the aortic baroreceptor reflex in the rat CVLM. It appears that neurons other than the vasodepressor neurons in the CVLM, at least in part, play a role in transmitting the aortic baroreceptor reflex. In addition, both NMDA and non-NMDA receptors may be responsible for the mediation of the reflex.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Naunyn-Schmiedeberg's archives of pharmacology 343 (1991), S. 439-446 
    ISSN: 1432-1912
    Keywords: 5-HT4 ; Oesophagus ; Rat ; ICS 205–930 ; Benzamides
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The present study was designed to characterize an “atypical” 5-hydroxytryptamine (5-HT) receptor mediating relaxation of the rat oesophageal tunica muscularis mucosae. All experiments were performed under equilibrium conditions, using pargyline to inhibit the oxidative deamination of indoleamines, and cocaine and corticosterone to inhibit neuronal and extraneuronal uptake. Under these conditions 5-HT (0.3–1000 nmol/l) produced a concentration-dependent relaxation of carbachol-induced tension. The concentration-effect curve to 5-HT was unaffected by potent antagonists for 5-HT1, 5-HT2, 5-HT3 and so called 5-HT1P receptors (metergoline, methysergide, ketanserin, ondansetron, N-acetyl-5-hydroxytryptophyl-5-hydroxytryptophan amide), but was antagonized competitively by ICS 205–930 (pA2 = 6.7). Responses to 5-HT were mimicked by other indoleamines and substituted benzamides with the following order of potency: 5-HT ≥ 5-methoxytryptamine 〉 cisapride = α-methyl-5-HT = (S)-zacopride = renzapride 〉 (RS)-zacopride 〉 5-carboxamido-tryptamine = metoclopramide = (R)-zacopride 〉 tryptamine 〉 2-methyl-5-HT. ICS 205–930 afforded similar pA2 values (6.0–6.7) against each agonist, indicating a common site of action. Concentration-effect curves to 5-HT were not affected by tetrodotoxin or indomethacin, sugesting that 5-HT-induced relaxation of the tunica muscularis mucosae was mediated via a postjunctional receptor, independent of endogenous prostanoids. The pharmacological profile of the 5-HT receptor in the rat oesophageal tunica muscularis mucosae correlates well with the 5-HT4 receptor characterized recently in both the CNS and gastro-intestinal tract.
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  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Naunyn-Schmiedeberg's archives of pharmacology 343 (1991), S. 595-602 
    ISSN: 1432-1912
    Keywords: Periaqueductal gray slices ; [3H]Noradrenaline release ; [3H]Dopamine release ; [3H]5-Hydroxytryptamine release ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The periaqueductal gray is a brain region of considerable interest. It is innervated by monoamine-containing neurons as well as by a variety of peptidergic fiber systems, and it participates in the regulation of various functions. Virtually nothing is known about monoamine release in the periaqueductal gray and its receptor-mediated modulation. We therefore studied the release of radioactivity from periaqueductal gray slices preloaded with tritriated monoamines, using an in vitro superfusion method. The release of radioactivity from superfused periaqueductal gray slices after preloading of the tissue with [3H]noradrenaline increased upon electrical stimulation in a frequency-dependent manner. The stimulus-evoked release of radioactivity was Ca2+-dependent. Clonidine reduced and yohimbine enhanced the release. The inhibition curve for the effect of clonidine was shifted to the right in the presence of 10−6 M yohimbine. While phenylephrine, isoprenaline, SK&F 38393, quinpirole, carbachol, [Arg8]vasopressin, α-MSH and ACTH-(1-24), at a concentration of 10−6 M, did not influence the electrically evoked release of radioactivity, [Leu5]enkephalin reduced it. The selective μ-opioid receptor agonists [d-Ala2,NMePhe4,Gly-ol5]enkephalin and [d-Arg2,Lys4]-dermorphin-(1–4)-amide reduced the release of radioactivity, whereas the selective δ opioid receptor agonist [d-Pen2,d-Pen5]enkephalin and the selective K opioid receptor agonist U-69593 had no effect. In the presence of naloxone, which by itself had no effect on the release of radioactivity, the effect of [d-Arg2,Lys4]dermorphin-(1–4)-amide was abolished. These results show that the release of noradrenaline from periaqueductal gray slices is via a Ca2+-dependent. exocytotic process, and that it is modulated through α2-adrenoceptors as well as via μ-opioid receptors. Though the overflow of radioactivity from slices preloaded with [3H]dopamine in the presence of desipramine was measurable, there are reasons to assume that we are dealing here with the release of tritiated catecholamines from a population of nerve endings consisting of noradrenergic and dopaminergic terminals. The release of radioactivity from periaqueductal gray slices preloaded with [3H]5-hydroxytryptamine upon elevation of the K+ concentration in the superfusion medium was much more pronounced than that induced by electrical stimulation. The K+-evoked release of radioactivity was almost completely abolished in the absence of Cat2+; showing that the release is via a Ca2+-dependent process. 5-Hydrotryptamine reduced the K+-evoked release of radioactivity in a concentration-dependent manner.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Springer
    Cancer immunology immunotherapy 33 (1991), S. 50-53 
    ISSN: 1432-0851
    Keywords: Brain neoplasm ; Immunotherapy ; Interleukin-2 ; Lymphokine-activated killer cells ; Rat ; Splenocyte ; Thymocyte
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary We studied the lymphokine-activated killer (LAK) activity in splenocytes and thymocytes of rats with brain tumors chronologically from the early stage to the late stage, in order to clarify how much LAK activity would be developed at each stage. Simultaneously the natural killer (NK) activity in splenocytes, as one aspect of the host immunocompetence, was also determined. The splenic NK activity was significantly depressed in rats with brain tumors during the 2nd and 3rd weeks after tumor transplantation, as compared with normal controls. On the other hand, the splenocytes incubated with interleukin-2 showed the same killer activity in rats with brain tumors as in normal rats at all times. The LAK activity in thymocytes from rats with brain tumors was significantly higher than that of controls in the 1st and 2nd weeks and became equal to that of the controls during the 3rd week. The killer activity after incubation with interleukin-2 in thymocytes was superior to that in splenocytes throughout the experiment in both tumor-bearing rats and controls, which suggested that the precursor of LAK cells was not NK cells.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Springer
    Journal of molecular evolution 33 (1991), S. 442-449 
    ISSN: 1432-1432
    Keywords: Humans ; Mouse ; Rat ; Codon usage ; Mutation bias ; Selection
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary A new statistical test has been developed to detect selection on silent sites. This test compares the codon usage within a gene and thus does not require knowledge of which genes are under the greatest selection, that there exist common trends in codon usage across genes, or that genes have the same mutation pattern. It also controls for mutational biases that might be introduced by the adjacent bases. The test was applied to 62 mammalian sequences, the significant codon usage biases were detected in all three species examined (humans, rats, and mice). However, these biases appear not to be the consequence of selection, but of the first base pair in the codon influencing the mutation pattern at the third position.
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  • 10
    ISSN: 1432-2307
    Keywords: Bromocriptine ; Pituitary neoplasm ; Prolactin ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Conventional light microscopy, immunocyto-chemistry, electron microscopy and in situ hybridization were used to evaluate the effect of dopamine agonists (bromocriptine-LAR and bromocriptine) on the morphology of surgically removed prolactin (PRL)-producing pituitary adenomas. Dopamine agonist therapy resulted in decrease of serum PRL, clinical improvement and tumour shrinkage. Using light and electron microscopy cellular atrophy, interstitial and perivascular fibrosis were noted; in several tumours connective tissue accumulation was pronounced. The cellular response was not uniform. In some adenomas populations of large cells and small cells were distinguished. The large cells contained immunoreactive PRL and expressed the PRL gene indicating resistance to dopamine agonists. It appears that these cells retained the potential to secrete PRL and proliferate despite exposure to dopamine agonists. In the small cells, PRL immunoreactivity and PRL gene expression decreased providing evidence that both PRL release and synthesis were blocked. Small cells can persist in tumours after discontinuation of dopamine agonist medication suggesting these small cells are irreversibly suppressed and are not capable of regaining their endocrine function and proliferative capability. The formation of irreversibly suppressed PRL cells may explain why some PRL-producing adenomas do not recur after withdrawal of dopamine agonists.
    Type of Medium: Electronic Resource
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  • 11
    ISSN: 1432-2307
    Keywords: HLA-DR ; Phaeochromocytomas ; Paragangliomas ; Immunohistochemistry ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Twelve cases of phaeochromocytoma (PCC) and four cases of paraganglioma (PGG) were studied by immunohistochemistry and immunoelectron microscopy in order to demonstrate HLA-DR (Ia)-antigen-positive dendritic cells (IaDCs). Dense infiltration of IaDCs was detected in the majority of PCCs revealing high urinary or serum catecholamine levels, but in aggressively growing PCCs, a familial PCC and all PGGs, few IaDCs were demonstrated. Interestingly, these IaDCs were negative for S-100 protein. Although S-100-protein-positive sustentacular-like cells (SCs), morphologically similar to IaDCs, were also present, these were clearly distinguished from IaDCs by our double immunostaining method. Ultrastructurally, IaDCs had smooth or slightly indented nuclei and contained a moderate amount of endoplasmic reticulum, small mitochondria and vacuoles, extending elongated cytoplasmic processes. These results suggest that determination of the quantity of IaDCs is a highly effective method of assessing the character of PCCs, in particular, their prognosis.
    Type of Medium: Electronic Resource
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  • 12
    ISSN: 1432-2307
    Keywords: Cell-mediated cardiocyte injury ; Acute cardiac allograft rejection ; Mononuclear cellular infiltration ; Immunohistochemistry ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary To clarify the immune mechanism of cytotoxicity in acute cardiac allograft rejection, we observed interactions between cardiocytes and mononuclear cells using immunohistochemistry and light and electron microscopy. All allografted WKA rat hearts transplanted to F344 recipients stopped beating by the 7th day after the transplantation. The population of helper/inducer T cells (Th) and IL2R+ cells was large for the first 3 days, whereas that of cytotoxic/suppressor T cells (Tc-s) and macrophages increased from the 4th day. TheTh/Tc-s ratios were more than 2.0 until the 3rd day, then decreased to less than 1.0. In circulating T lymphocytes; theTh/Tc-s ratios were under 1.0 on the 1st, 6th and 7th days. Electron microscopically IL2R+ cells, Tc-s and macrophages were often seen in close contact with the plasma membrane of the cardiocytes. The majority of IL2R+ cells are NK cells, Tc-s andTh. Of these, the population of Tc-s was small until the 3rd day. Thus, NK cells play a pivotal role in the early stage of the rejection, and Tc-s and macrophages then aggravate cell-mediated cardiocyte injury.
    Type of Medium: Electronic Resource
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  • 13
    Electronic Resource
    Electronic Resource
    Springer
    Virchows Archiv 418 (1991), S. 515-522 
    ISSN: 1432-2307
    Keywords: Oesophagus ; Melanocyte ; Melanoma ; Ultrastructure ; Endoscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Four examples of an endoscopically detected oesophageal melanotic lesion were examined by light microscopy, light microscope histochemistry and transmission electron microscopy, and were compared with 13 control samples of normal oesophageal epithelium. By light microscopy, pigmented melanocytes lacking atypia and mitoses were observed amongst the keratinocytes in the basal layer of the oesophageal mucosa. Junctional activity was absent. The mechanism of pigmentation was studied and found to consist of: an increase in the number of melanocytes in the basal layer of the mucosa, an increase in the quantity of melanin in these melanocytes, transfer of melanin from melanocytes to keratinocytes and to macrophages and fibroblasts in the tunica propria. Since all the lesions demonstrated increased numbers of both melanocytes and melanosomes, the term oesophagealmelanocytosis rather thanmelanosis is suggested, to emphasise the essential character of the lesion as a cellular proliferation. The value of sampling these pigmented lesions during endoscopy is emphasised as a means of obtaining well-preserved material for the evaluation of a lesion which some authorities have viewed as a possible precursor for oesophageal malignant melanoma.
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  • 14
    ISSN: 1432-2307
    Keywords: Mitochondrial cardiomyopathy ; Ultrastructure ; Cytochromec oxidase deficiency ; Ventricular tachycardia
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary A 30-year-old woman presented with lifethreatening ventricular tachycardia without overt heart disease. Ultrastructural investigation of endomyocardial biopsy disclosed abnormally structured and often enlarged mitochondria. Morphometry revealed the ratio of volume density of mitochondria to myofibrils to be markedly increased to 0.667 as compared with five controls (mean: 0.46; range: 0.445–0.479). Investigation of mitochondrial respiratory chain enzymes revealed a 90% reduction in activity of cytochromec oxidase. Our data suggest that mitochondrial cardiomyopathy may induce malignant ventricular arrhythmias.
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  • 15
    Electronic Resource
    Electronic Resource
    Springer
    Urological research 19 (1991), S. 253-257 
    ISSN: 1434-0879
    Keywords: Microsurgery ; CO2 laser ; Nd:YAG laser ; Rat ; Vascular anastomosis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary A comparative study was undertaken in 81 rats to investigate a CO2 and Nd:YAG laser system for laserwelded anastomosis of the femoral vein. Conventionally sutured anastomoses (CMSA) served as controls. Laserwelded anastomosis (LAMA) was easier and could be performed 30% faster than CMSA. Postoperative investigations included patency tests, postmortem examinations and light and electron microscopy. Aneurysms were not seen. Foreign-body reaction was more pronounced in CMSA. Patency rates for CO2-LAMA and CMSA were equal, whereas Nd:YAG-LAMA resulted in significantly higher rate of early postoperative thrombosis (P〈0.01). Because of its physical properties, the CO2-laser system seems to be better suited for laser welding of delicate structures such as the rat femoral vein.
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  • 16
    Electronic Resource
    Electronic Resource
    Springer
    Urological research 19 (1991), S. 141-144 
    ISSN: 1434-0879
    Keywords: Experimental ; Bacterial ; Prostatitis ; Rat ; Antibiotics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Experimental acute bacterial prostatitis in rats was induced by four different routes of bacterial inoculation. The most simple and reproducible method of producing bacterial prostatitis was to instil the bacterial suspension into the prostatic urethra after the administration of an appropriate antibiotic to prevent associated pyelonephritis.
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  • 17
    ISSN: 1434-0879
    Keywords: Diet ; Calcium ; Magnesium ; Phosphorus ; Struvite stones ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary After feeding various diets we studied the effects of dietary calcium, magnesium and phosphorus on the formation of struvite stones in rats with urinary tract infections, and also studied the effects of the administration of vitamin D3 and aluminium gel on stone formation. A low-magnesium diet decreased urinary magnesium and prevented stone formation, but a medium-calcium diet did not significantly decrease stone weight. A high-calcium diet decreased urinary phosphorus and inhibited stone formation. A high-calcium and high-phosphorus diet decreased urinary excretion of magnesium and inhibited stone formation. Although the administration of vitamin D3 did not inhibit stone formation, aluminium gel decreased the urinary level of phosphorus and prevented stone formation. A marked decrease in urinary magnesium and/or phosphorus may prevent struvite stone formation in rats with urinary tract infections.
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  • 18
    Electronic Resource
    Electronic Resource
    Springer
    Urological research 19 (1991), S. 319-322 
    ISSN: 1434-0879
    Keywords: Varicocele ; Rat, Histology ; Ultrastructure ; Temperature ; Infertility
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary With no consistent animal prototype for the study of varicocele, we set out to create a model in the rat by complete ligation of the main branch of left spermatic vein (MBSV) or by partial ligation of the left renal vein. Three months later, the histology, ultrastructure and temperature of the testis and epididymis were studied. Microscopically, spermatogenic arrest was the most frequent anomaly seen. The most frequently noted ultrastructural change of the testis was distension of smooth endoplasmic reticula in Sertoli cells. The microvilli of columnar epithelia in epididymis were sparse and showed local defects. Lesions and increased temperatures in the testis and epididymis induced by the ligation of the left MBSV were similar to those seen in partial ligation of the left renal veins, with no significant differences between left and right. Significant differences were found, however, on comparison with the controls.
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  • 19
    ISSN: 1432-0568
    Keywords: Glutamine ; Glutamate ; Cerebellum ; Immunocytochemistry ; Glia ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The cellular and subcellular localization of glutamine, a major glutamate precursor, was studied by means of an antiserum raised against glutaraldehydefixed glutamine. Ultrathin sections from the cerebellar cortex of rat and baboon (Papio anubis) were incubated sequentially in the primary antiserum and in a secondary antibody coupled to colloidal gold particles. The labelling intensity was quantified by computer-aided calculation of gold particle densities. High levels of immunoreactivity occurred in glial cells (Bergmann fibres, astrocytes, and oligodendrocytes), intermediate levels in cell bodies and processes of granule cells, and low levels in terminals of presumed GABAergic or glutamatergic fibres (terminals of basket and Golgi cells, and of parallel, mossy, and climbing fibres). The labelling intensity of Purkinje cells showed some variation, but never exceeded that in glial cells. Within the nerve fibre terminals, the glutamine-like immunoreactivity showed some preference for mitochondria, but was otherwise evenly distributed. The predominant glial localization of glutamine was also obvious in light microscopic preparations processed according to the postembedding peroxidase-antiperoxidase procedure. Gold particle densities over different types of profile in glutamine immunolabelled sections were compared with particle densities over the corresponding types of profiles in neighbouring sections labelled with an antiserum to glutaraldehyde-fixed glutamate. The glutamate/glutamine ratio, expressed arbitrarily by the ratio between the respective gold particle densities, varied by a factor of about 6, with the highest ratio in the putative glutamatergic mossy and parallel fibre terminals, and the lowest ratio in glial elements. The remaining tissue components displayed intermediate ratios. The present study provides direct morphological evidence for the existence in the brain of distinct compartments with differing glutamate/glutamine ratios.
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  • 20
    Electronic Resource
    Electronic Resource
    Springer
    Anatomy and embryology 184 (1991), S. 269-273 
    ISSN: 1432-0568
    Keywords: Rat ; Skeletal muscle ; Muscle fibre types ; Histochemistry ; Cluster analysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Different histochemical identification methods for muscle fibre types have been introduced over the years. Most of them have been based on myosin ATPase activity after different kinds of preincubations, alone or in combination with oxidative enzymes. Comparative studies have shown, however, that the different methods result in nonidentical subgroups of type II fibres. Optical density values of individual fibres after incubation of serial sections for alkali- or copper-preincubated ATPase, NADH-TR, and fibre diameter, combined in two-dimensional plots, have for a long time been used in our laboratory to separate three subgroups of type II fibres. A cluster analysis, based on the data mentioned above, results in three subgroups of type II fibres in rat plantaris muscle. In comparison, earlier studies comparing different histochemical methods and reporting lack of correspondence between them have been based on two subgroups of type II fibres only. It is suggested that part of the lack of correspondence is due to unequal and incomplete separation by the methods used in the comparative studies, and that the three subgroups of type II fibres identified in the cluster analysis are type IIA, IIX and IIB, respectively. The need for a consensus on a common basis for histochemical identification of muscle fibre types is emphasized.
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  • 21
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    Anatomy and embryology 183 (1991), S. 537-544 
    ISSN: 1432-0568
    Keywords: Synovial membrane ; Development ; Ultrastructure ; Scanning electron microscopy ; Mouse
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The prenatal and postnatal development of the mouse knee joint was investigated by transmission and scanning electron microscopy. In the prenatal stage, following the appearance of a narrow intercellular cleft between two skeletal elements on the 16th fetal day, clefting extended into the lateral synovial mesenchyme. In some regions, the extension of the cleft was very rapid, but in a certain region (future fat pad region), it was somewhat slower. Macrophage-like cells appeared in the synovial mesenchyme on the 16th fetal day, and then increased in number, and were distributed as if they were clustering around the presumptive clefting zone in the future fat pad region on the 17th–18th fetal day. This suggests that macrophage-like cells may participate in joint development, as they phagocytize and remove some kinds of solid extracellular matrix, and facilitate the cleft extension. In the early postnatal stage, scanning electron microscopic observations showed that there were two different types of cell in the synovial lining. One of them exhibited a surface morphology corresponding to that of macrophages: a spherical cell body and numerous pseudopodia. The other type of cell exhibited various cell shapes with many cytoplasmic processes extending along the synovial surface.
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  • 22
    ISSN: 1432-0568
    Keywords: Ontogeny ; Cerebrovascular innervation ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The development of cerebrovascular nerves containing noradrenalin (NA), acetylcholinesterase (AChE), neuropeptide Y (NPY), and vasoactive intestinal polypeptide (VIP) was studied in rats from before birth to adulthood. All these nerves entered the cranial cavity along the cerebral carotid, internal ethmoidal, and vertebral arteries during the early stages of development, but the subsequent growth and distribution of NA-containing and NPY-immunoreactive (IR) nerves differed greatly from that of AChE-positive and VIP-IR nerves. NA-containing and NPY-IR nerves extended rapidly from the cerebral carotid artery and spread over all the major arteries of the internal carotid system by postnatal day 3, as well as descending the posterior ramus of the cerebral carotid to mingle with nerves from the vertebral artery around the mid-basilar artery by day 5. AChE-positive and VIP-IR nerves from the internal ethomoidal artery covered the whole internal carotid system during the first postnatal week, and projected to the upper basilar artery after the second week, while those from the cerebral carotid artery remained limited to the middle cerebral artery throughout development. By day 21, all major arteries of the internal carotid system had dense plexuses of the four nerve types that were similar to those observed in adult rats. The vertebrobasilar system also had a well-organized network of NA-containing and NPY-IR nerves, but only a poor supply of AChE-positive and VIP-IR nerves. Even on day 30, the latter two nerve types were sometimes absent from the middle to caudal basilar artery, owing to a lack of interdigitation by nerves from the internal ethomoidal and vertebral arteries.
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  • 23
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    Anatomy and embryology 184 (1991), S. 47-53 
    ISSN: 1432-0568
    Keywords: Wing bud ; Endothelial cell ; Development ; Ultrastructure ; Morphometry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The microvascular endothelium of the chick wing bud at stages 22, 27, and 32 was evaluated by ultrastructural morphometry. The rationale for this study is based on the hypothesis that endothelial cells exhibit variation in structure and function during cytodifferentiation. The microvessels had a luminal diameter range such that they were classified as capillaries. The thin continuous endothelium was devoid of a basal lamina. The endothelium had a very small number of plasmalemmal vesicles; vacuoles were however present for all stages and in some cases were abundant. The temporal findings were that endothelial cell thickness increases, plasmalemmal vesicle densities decrease, and the densities of cytoplasmic vacuoles increase. The spatial results were that endothelial cells in proximal regions of the limb have a greater thickness, contain fewer vesicles and have more vacuoles than those in distal regions. In general, these results indicate that endothelial ultrastructural heterogeneity occurs within a 31/2 day timespan of wing bud development. The discussion considers the results with regard to recent reports on endothelial cell heterogeneity.
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  • 24
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    Anatomy and embryology 184 (1991), S. 65-70 
    ISSN: 1432-0568
    Keywords: Stereology ; Development ; Coronaries ; Corrosion casts ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary To study myocardial vascular development, stereological parameters were estimated in 24 Wistar rat hearts of six different age groups, from newborn to adult. The vascular surface density showed a sharp increase in the first 2 weeks, a peak around the age of 2 weeks, and then a steady decrease until it flattened in adulthood. In contrast, the vascular volume percentage, when plotted against age, decreased continuously with the greatest change in the first week, after which the curve flattened. These findings are compatible with an increase in the number of capillaries with a concomitant decrease of their diameters. Qualitative scrutiny of the histology did indeed support the idea that vessels become thinner. Reconstructions of the histological sections showed the same change three dimensionally. The reconstructions also demonstrated very small holes that seemed to go through the capillaries in the younger stages. Corrosion casts of the blood vessels were made using a casting resin. This was injected into the umbilical artery of rat embryos from 15 days gestation to birth. In postnatal rats of six age groups methacrylate was injected directly into the left ventricle. These casts supported the stereological data by showing an increase in number and decrease in diameter of capillaries, while during pre- and postnatal development, the intervascular spaces lengthened from small, irregular spaces to long, rectangular ones. Small holes, the probable precursors of such spaces, were clearly visible in the wider vessels of the youngest stages. All data point to an interesting mode of capillary growth, i.e. growth by division of existing vessels.
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  • 25
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    Anatomy and embryology 184 (1991), S. 363-369 
    ISSN: 1432-0568
    Keywords: Taste organs ; Amphibia ; Development ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary In tadpoles ofRana temporaria two successive generations of taste organs: taste buds (TBs) and taste disks were studied. The TBs are located in the apices of oral premetamorphic papillae. Each TB consists of vertically elongated receptor cells (probably taste) and supporting cells. No basal (Merkel) cells were observed there. Morphologically, two types of receptor cells have been distinguished in a TB. Complete synaptic structures were observed in the TBs between the 30th and 41st of Gosner's (1960) developmental stages, though synaptic vesicles occur already at stage 26. The taste disks consist of taste cells, supporting cells and basal cells. Dense-core synaptic vesicles occur in the gustatory cells at stage 41, but complete synaptic structures were not observed earlier than at stage 45. Synaptic junctions observed at some of the gustatory cells seem to be reciprocal (bidirectional).
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  • 26
    ISSN: 1432-0568
    Keywords: Tachyglossus aculeatus (echidna) ; Echidna bill ; Sensory receptors ; Electroreceptor ; Mechanoreceptor ; Trigeminal nerve ; Monotreme ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The gross anatomy and nerve supply of the bill of echidna (Tachyglossus aculeatus) is described in relation to its function as an outstanding sensory organ. The sensory innervation of the skin of the echidna snout was investigated by means of frontal serial sections, after decalcification of the specimens. A comprehensive light and electron microscopic description of the location and fine structure of cutaneous sensory receptors of the trigeminal system was made by this means. The encapsulated and non-encapsulated Ruffini receptors, the types of other free receptors in the connective tissue and the Merkel cell receptor do not differ morphologically from those of higher mammals, whereas the pacinian-like corpuscle shows a unique organization of its outer core. This is composed of large perineural cells containing a unique reticulum of parallel-orientated endoplasmic membranes. Lamellated corpuscles, seen in isolation or in association with push rods, are numerous in the snout and in the tip of the tongue of echidna. Push rod receptor organs occur in the hairless skin of the bill with a very dense array at its rostral end and in the pseudopalatal ridges. Gland duct receptors are restricted to the skin adjacent to the nostrils and the mouth opening, including the pseudopalatal plates. Only about one quarter of the total number of 400 seromucous glands receive a sensory innervation of their intraepidermal duct segment. Within each innervated gland two types of receptor terminals are identified. The distributions of the different receptor types are mapped for different regions of the skin, the mucous membrane of the nasal and oral vestibule and the tip of the tongue. The fine structure of nerve terminals is discussed from a comparative anatomical point of view, and some speculations are made about possible transduction processes that underlie the known electrophysiological properties. The sensory organs such as the “push rod” and “gland duct receptor”, and most of their sensory terminals, are less differentiated in echidna snout than in the platypus (Ornithorhynchus anatinus) bill.
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  • 27
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    Acta neuropathologica 82 (1991), S. 295-301 
    ISSN: 1432-0533
    Keywords: Hyaline inclusions ; Motor neuron disease ; Amyotrophic lateral sclerosis ; Immunocytochemistry ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary We investigated hyaline inclusion bodies (HI) immunocytochemically and ultrastructurally in six cases of sporadic motor neuron disease (MND). All HI contained large amounts of ubiquitin and some HI were stained at the core or the center with anti-neurofilament antibody, with the surrounding halo unstained. No HI were stained with antibodies raised against cytoskeletal proteins such as high-molecular weight microtubule-associated proteins and phosphorylated tau. Ultrastructurally, HI were chiefly composed of filaments measuring about 20 nm in diameter thicker than neurofilaments, and contained fine granules and frequently one or more of four characteristic profiles, i.e., small electron-dense materials resembling Bunina bodies, bundles of tubular filaments measuring approximately 20 nm in diameter, large electron-dense cores, and focal accumulations of randomly arranged neurofilaments. Hyaline inclusions can be regarded as one of the characteristic markers for sporadic MND as well as familial amyotrophic lateral sclerosis. Hyaline inclusions have a markedly heterogeneous ultrastructure and, therefore, differences in immunoreactivity with antineurofilament antibodies are not unexpected.
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  • 28
    ISSN: 1432-0533
    Keywords: Meningioma ; Microcystic meningioma ; Vacuolated meningioma ; Arachnoid trabecular cell ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Three cases of meningiomas which had abundant small vacuoles in the tumor tissue are reported. By electron microscopy, the tumor cells exhibited long and thin processes, the tips of which were united by desmosomes. The tumor tissue was revealed to have wide extracellular spaces which corresponded to the vacuoles observed by light microscopy. In previous literature, various terms have been used when referring to this meningioma, such as microcystic meningioma or vacuolated meningioma. Since the ultrastructure of the tumor showed similarity to that of normal arachnoid trabecular cells, we propose to call the tumor “arachnoid trabecular cell meningioma” denoting its morphological nature clearly.
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  • 29
    ISSN: 1432-0533
    Keywords: Galactosialidosis ; Neuronal storage disease ; Neuropathology ; Ultrastructure ; Neuronal loss
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The neuropathological findings in a 13-year-old Japanese male showing decrease of sialidase and β-galactosidase activities are reported. The patient was the product of normal pregnancy to consanguineous parents. He started to sit at 8 months, stand at 20 months and walk at the age of 2; mental retardation, visual disturbance, cerebellar ataxia, myoclonus and epilepsy developed by the age of 10, and he died at 13. Neuropathological investigation revealed neuronal loss and storage. Severe loss of neurons was observed in the thalamus, globus pallidus, lateral geniculate body, gracile nucleus, Purkinje and retinal ganglion cells. Marked ballooning was seen in the Betz cells and neurons in the basal forebrain, the motor neurons in the cranial nerve nuclei and spinal cord, and in the trigeminal and spinal ganglia. The storage material varied in staining from region to region and from neuron to neuron. Electron microscopic investigation revealed a variety of intracytoplasmic and intranuclear inclusions: membranous cytoplasmic bodies, parallel, wavy-lamellar or tortuous tubular structures, lipofuscin-like irregular-shaped pleomorphic bodies, and cytoplasmic vacuoles with fine granules and lamellar materials. The severity of the neuronal loss did not seem to correlate with the amount of the storage materials, but with the presence of tortuous tubular inclusion.
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  • 30
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    Acta neuropathologica 82 (1991), S. 402-407 
    ISSN: 1432-0533
    Keywords: Gangliocytoma ; Ultrastructure ; Catecholamines ; Hypertension ; Spinal cord
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary An 8-year-old boy developed severe systemic hypertension during resection of an intramedullary tumor. The histological, ultrastructural and immunocytochemical characteristics of the tumor are those of a gangliocytoma. Based on the demonstration of tyrosine hydroxylase in neuronal tumor cells, it is postulated that catecholamine secretion was responsible for the systemic hypertension.
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  • 31
    ISSN: 1432-0533
    Keywords: 72-kDa heat-shock protein ; Neuronal necrosis ; Forebrain ischemia ; Immunohistochemistry ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary We evaluated the relationship between the induction of the 72-kDa heat-shock protein (hsp 72) and the presence of necrotic neurons in the rat hippocampus, 48 h after an 8-min episode of forebrain ischemia in eight rates. Hsp 72 was detected using the monoclonal antibody C92 on vibratome brain tissue sections. Hematoxylin and eosin (H&E) staining on adjacent paraffinembedded sections was used to determine histopathological features. All morphologically intact CA1/2 neurons, 70% of which are destined to become necrotic 7 days after ischemia, exhibited intense hsp 72 staining, while necrotic or damaged neurons were devoid or low in hsp 72. Hsp 72 was also detected in CA3 neurons destined to survive 7 days after ischemia. Blood vessels positive for hsp 72 were detected in focal brain regions, in which severely damaged neurons were either devoid or low in hsp 72 staining. Occasional glial cells expressed hsp 72 in both normal and damaged brain regions. Hsp 72 response to a transient forebrain ischemia seemingly reflects differences in the selective ischemic vulnerability of CA1/2 and CA3 neurons. Further, the presence of hsp 72 within a neuron is likely only a marker of stress and is not necessarily indicative of eventual neuronal survival.
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  • 32
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    Acta neuropathologica 81 (1991), S. 408-417 
    ISSN: 1432-0533
    Keywords: Werdnig-Hoffmann disease ; Immunocytochemistry ; Ultrastructure ; Cytoskeleton ; Ubiquitin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Neuronal alterations in two cases of Werdnig-Hoffmann disease (WH) were investigated immunocytochemically and ultrastructurally. Ballooned neurons (BNs) were found in anterior horn, Clarke's column, dorsal root ganglion and thalamus. Anti-phosphorylated neurofilament antibodies preferentially stained the peripheral perikarya and proximal neuronal processes of BNs, whereas anti-ubiquitin antibodies preferentially stained the central perikarya of BNs. Ultrastructurally, BNs showed degenerative changes ranging from a diffuse increase of neurofilaments to a centrally accentuated accumulation of mitochondria and vesicular or membranous profiles. Our studies suggest that ubiquitinated degradation products accumulate in the center of the BN's perikaryon and displace aberrantly phosphorylated neurofilaments to the periphery. BNs in WH probably reflect an intrinsic alteration in the metabolism of neurofilaments that is associated with regressive changes in the neuron and eventually neuronal death.
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  • 33
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    Acta neuropathologica 82 (1991), S. 21-32 
    ISSN: 1432-0533
    Keywords: Muscle ; Regeneration ; Denervation ; Ultrastructure ; Snake toxin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary This study examines the level to which muscle regeneration proceeds in the absence of innervation. Regeneration was monitored in rat soleus muscles following localised injection of a snake toxin, notexin. Muscles which had been concomittantly denervated were compared with those that were normally innervated. Until 3–4 days following toxin administration regeneration is identical in both groups. The muscles contain new myotubes in place of the degenerated “parent” fibres. Thereafter, the non-denervated muscles grow rapidly and by 28 days their myofibres attain the size of those from the contralateral controls. Growth of denervated regenerating muscles, however, is retarded and is superseded by a gradual atrophy. In such muscles we further identify ultrastructural abnormalities from 7 days post-injection. These a re loss of individual myosin filaments and the presence of immature and abnormal configurations of the transverse system and triads. We, thus, conclude that innervation is an obligatory requirement for the restoration of normal myofibrillar and sarcotubular morphology, as well as growth, but is not necessary for the neo-formation of myofibres.
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  • 34
    ISSN: 1432-0533
    Keywords: MPS I-S ; Skin biopsy ; Ultrastructure ; Bone marrow transplant
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary An 11-year-old girl with mucopolysaccharidosis I Scheie phenotype (MPS I-S) received a bone marrow transplant (BMT) from her heterozygous HLA-identical LMC-non-reactive mother. Multidisciplinary studies were carried out and results evaluated 21 months after transplantation. Herein we report the ultrastructural findings pre-and post-BMT in skin. Multidisciplinary studies are commonly used to evaluate the benefits of metabolic correction following BMT in some MPS and other inherited metabolic disorders, and changes in morphology have been described in liver and few other tissues. In this case, we elected skin, since connective tissue is universally involved in MPS and is safely and easily obtainable. Comparison of skin biopsy specimens taken before and after BMT showed a considerable change in dermal fibroblast morphology, with marked reduction in cell size and the number and size of abnormal lysosomes, thus indicating the clearance of storage. Our results demonstrate that dermal cells respond to enzyme replacement therapy in MPS I-S, with the clearance of glycosaminoglycan lysosomal accumulation in connective tissue fibroblasts, which had near-normal morphology 21 months after BMT. Therefore, the practice of skin biopsy after BMT in MPS and other metabolic disorders in which dermal cells are involved should be encouraged.
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  • 35
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    Anatomy and embryology 183 (1991), S. 81-87 
    ISSN: 1432-0568
    Keywords: Trachea ; Airways ; Smooth muscle ; Sensory receptors ; Vagus nerve ; Guinea-pig ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The trachea of guinea-pigs was stained as a whole-mount preparation with the zinc iodide-osmium technique. A distinct class of nerve endings was observed associated with the tracheal muscle. The endings, issued from myelinated fibres of the vagus nerve via the recurrent laryngeal nerve, are distributed on either side of the midline and ventral to the tips of cartilages. They are interpreted as afferent nerve endings that may correspond to slow adapting stretch receptors identified by physiological studies. Each nerve contributes predominantly, but not exclusively, to the receptors of the ipsilateral side. There are 120–180 receptors along the full length of the guinea-pig trachea, their density being higher at the cranial end. The receptors are variable in size and structural complexity, and, to some extent, also in spatial orientation, but distinct subtypes are not recognizable. Receptors of similar morphology and distribution are found also in the rat trachea. The receptors can also be visualized with a cytochrome oxidase method for nerve endings, but they do not stain with immunohistochemistry for the neuropeptides substance P, calcitonin gene-related peptide, vasointestinal polypeptide and neurotensin.
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  • 36
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    Anatomy and embryology 183 (1991), S. 129-134 
    ISSN: 1432-0568
    Keywords: Vasopressin ; Endothelium ; Pulmonary artery ; Immunocytochemistry ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The localization of arginine-vasopressin in the endothelial cells of rat pulmonary artery was investigated by immunocytochemistry at the light and electron microscopic levels. The immunogold silver staining method was used for light microscopy of sheets of endothelium, removed from the artery, and the pre-embedding peroxidase-antiperoxidase technique was used for electron microscopy of cross sections of the artery. With both of the methods used, numerous vasopressin-positive endothelial cells were observed. None of the subendothelial elements showed labelling for vasopressin. The results are discussed in terms of the involvement of the endothelium in local control of the pulmonary circulation.
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  • 37
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    Anatomy and embryology 183 (1991), S. 483-489 
    ISSN: 1432-0568
    Keywords: ChAT ; Cochlea ; Olivocochlear system ; Development ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Several studies present a great deal of information about putative efferent neurotransmitters and their distribution in the adult and developing cochlea. Anatomical mapping of outer hair cell efferent fibres during ontogeny is still not available. Using quantitative electron microscopy in combination with immunocytochemistry, the distribution of ChAT-like immunoreactivity in the developing rat was investigated. Adult-like immunoreactivity in the whole cochlea is first observed in 30-day-old rats. We localized the adult-like immunoreactivity in all efferent fibres and synapses of the outer hair cells along the entire cochlear duct. An adult-like reaction in the whole cochlea could be observed on the 25th day after birth in two out of three cases. On the 20th postnatal day, no adult-like ChAT immunoreactivity was found, with the exception of one case where labelling was seen in the basal region only. The adult-like ChAT immunoreactivity on the 30th day, 2–3 weeks after the onset of hearing, is the latest maturation of all features of the organ of Corti so far investigated. Synaptogenesis of the outer hair cell efferents reaches an adult-like appearance already on the 16th day after birth.
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  • 38
    ISSN: 1432-0533
    Keywords: Blood-brain barrier ; Ischemic edema ; Lanthanum ; Cerebral endothelium ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The distribution patterns of ionic Lanthanum (La3+; mol.wt. 139) were evaluated after 15, 30 and 60 min of middle cerebral artery occlusion in perfused-fixed rats. Blood-brain barrier (BBB) permeability to Evans blue (EB) and horseradish peroxidase (HRP; mol. wt. 40,000) in vivo was also evaluated. Brain tissue specific gravity was measured. An increase in brain water content was found as early as 30 min following occlusion. HRP and EB extravasation was not observed. La3+ crossed the interendothelial clefts of venoles and capillaries at 30 and 60 min and was seen in both extracellular and intracellular brain compartments at 60 min. La3+ extravasation was seen in nonedematous areas bordering the regions of water accumulation. Our findings suggest that the early phase of incomplete continuous ischemia is accompanied by changes in BBB permeability and the interendothelial clefts of venoles and capillaries seem to represent one of the early sites of ischemic damage.
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  • 39
    ISSN: 1432-0533
    Keywords: Hyperplasia ; Pituitary ; Pathology ; Prolactin ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Prolactin cell adenoma is the most frequently found lesion in surgically removed pituitaries of patients with hyperprolactinemia. However, in several instances, instead of prolactin cell adenoma, other lesions are encountered by morphological investigation. We report here the morphological findings in a patient with hyperprolactinemia who underwent transsphenoidal pituitary surgery for suspected prolactin cell adenoma. A morphological diagnosis of tumor could not be confirmed and massive diffuse prolactin cell hyperplasia was identified. The aim of this publication is to describe the lesion by histology, immunocytochemistry, electron microscopy, and in situ hybridization and to call attention to primary prolactin cell hyperplasia which can mimic prolactin cell adenoma.
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  • 40
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    Acta neuropathologica 82 (1991), S. 217-224 
    ISSN: 1432-0533
    Keywords: Hydrocephalus ; Rat ; Cerebral cortex ; Cortical cell density ; Capillary density
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Hydrocephalus in the H-Tx rat first develops in late gestation and causes death at 4–7 weeks. The effect of hydrocephalus on overall cortical dimensions and on five specific regions (frontal, sensory-motor, parietal, auditory and visual) has been studied by quantitative light microscopy at 10 and 30 days after birth. The lateral ventricle volumes in hydrocephalic rats were about 40x larger than controls and increased fourfold between 10 and 30 days. Cortical volume was reduced by a small amount at 10 days but was larger in hydrocephalics at 30 days. Thinning of the cortical mantle was severe with disruption of the laminar structure, particularly in the auditory and visual regions, where it was already present at 10 days. The density of cortical cells (neurones and glia) was not altered in hydrocephalics at 10 days but was reduced in all regions at 30 days. Estimates of total cell number suggest that the lower density was not associated with an overall loss of cells. Capillary numerical density was not affected by the hydrocephalus at 10 days after birth but by 30 days it was significantly lower, particularly in the worst-affected posterior regions. The results show that the cerebral cortex is severely distorted and that in advanced hydrocephalus, although overall cell number is not affected, both cell density and capillary density are lower by up to 30%.
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  • 41
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    Acta neuropathologica 81 (1991), S. 546-551 
    ISSN: 1432-0533
    Keywords: Rat ; Sciatic nerve ; Mineralization ; Aging ; X-ray microanalysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary A spontaneous mineralization of the sciatic nerve of senescent specific pathogen-free-bred rats (aged 42 months) is reported. Deposits were found in the endoneurium of different branches of the nerve at mid-thigh level. They appeared as small discrete deposits or as large tubular-shaped concretions, probably formed by the growth and merger of the smaller deposits. Some of the concretions were found in close proximity to blood vessels. Deposits consisted of dense aggregations of randomly entangled spicules spreading within bundles of collagen fibrils. Calcium was detected by histochemistry and X-ray dispersion microanalysis. Phosphorus was also found, possibly associated with calcium to form hydroxyapatite.
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  • 42
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    Acta neuropathologica 82 (1991), S. 420-424 
    ISSN: 1432-0533
    Keywords: Blastomycosis ; North American Blastomy-cosis ; Brain tumor ; Opportunistic infection ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Except for isolated case reports, blastomycosis has not been identified as a significant problem in immunosuppressed patients. We describe an unusual case with blastomycotic infection of a cerebral glioma in a 56-year-old man who underwent radiotherapy for his tumor and died of fulminant blastomycotic pneumonia. This is believed to be the first reported case of Blastomyces dermatitidis infection of a cerebral glioma. The light microscopic and ultrastructural features of B. dermatitidis, the giant forms of which were encountered in our patient, are described, and the role of immuno-suppression due to steroid therapy in the pathogenesis of this fulminant infection are reviewed.
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    Acta neuropathologica 81 (1991), S. 562-571 
    ISSN: 1432-0533
    Keywords: Scrapie ; Ultrastructure ; Vacuolation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Ultrastructural examination of the superior colliculi of mice intraocularly inoculated with the ME7 strain of scrapie showed vacuolation early in the course of infection. Brains were examined between 85–260 days after monocular inoculation with scrapie. The mean incubation period for the development of clinical disease was 302 days. Vacuolation was seen initially in the contralateral superior colliculus and subsequently in the ipsilateral colliculus. In coded trails light microscopical vacuolation was seen from 218 days but ultrastructural examination showed that sparse vacuoles were inconsistently present in either or both of the ipsilateral and contralateral colliculi from 85 days; frequent vacuoles were seen from 190 days. Scrapie-induced vacuoles were differentiated from vacuoles present in control tissue by the presence of loculation or by a limiting double membrane which showed protrusion or proliferation of the innermost lamella. Vacuolation was seen in neuronal perikarya, myelinated fibres, dendrites and axonal presynaptic terminals. Vacuoles of myelinated fibres were observed within myelin and possibly also in the inner tongue of oligodendroglial cytoplasm. Whorled membrane configurations were also seen. Tubulovesicular particles, 40 nm in diameter, were recognised in two scrapie-infected mice. It is suggested that some scrapie vacuoles arise as a result of incorporation of abnormal membrane into organelles, possibly mitochondria, in neuronal perikarya and neurites and probably also within oligodendroglial cytoplasm and myelin.
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  • 44
    ISSN: 1432-069X
    Keywords: Inflammatory linear epidermal naevus ; Keratinization ; DACM ; Involucrin ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Skin lesions of three patients with inflammatory linear verrucose epidermal naevus (ILVEN) were examined. Histologically, orthokeratosis and parakeratosis were alternately seen in the acanthotic epidermis. By N-(7-dimethylamino-4-methyl-3-coumarinyl)maleimide staining, the horny cells in the parakeratotic epidermis showed a cytoplasmic SH pattern and a weak membranous SS pattern. The orthokeratotic epidermis revealed an increased involucrin expression, whereas the parakeratotic epidermis showed almost no involucrin expression. Ultrastructurally, in the parakeratotic epidermis, the living keratinocytes had prominent Golgi apparatuses and vesicles in the cytoplasm. In the intercellular spaces in the upper spinous layer through to the lower horny layer, an electron dense, homogeneous substance was deposited. The cytoplasm of the horny cells was filled with keratin filaments and contained remnants of nucleus and cytoplasmic membrane structures, and some lipid droplets. The marginal band formation was incomplete. Most of these ultrastructural abnormalities were not found in the orthokeratotic epidermis. There are both similarities and differences in histopathogenesis of the parakeratotic epidermis between ILVEN and psoriasis. A unique finding was the lack of involucrin expression in the ILVEN parakeratotic epidermis.
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  • 45
    ISSN: 1432-069X
    Keywords: Rhino mouse skin ; All-trans retinoic acid ; CD271 ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The histological and ultrastructural effects following 3 weeks' topical treatment with two agents (all-trans retinoic acid and a new synthetic retinoid-like substance, CD271) were evaluated on the epidermis and the epithelial wall of the pseudocomedones in rhino mouse skin. The comedolytic effects of these drugs were similar, and consisted of a reduction of the utricular diameter, with normalization of follicular units. Morphological examinations revealed a hyperplastic response with an increase in the number of cell layers of both epidermis and follicular epithelium, and modifications in keratinocyte differentiation. Ultrastructural changes in the epidermis and epithelial wall were observed mainly in the granular and horny layers, with increased desquamation, and a decrease in the cohesiveness of corneocytes. During the first week of treatment, some cutaneous toxic effects were noticed, but they normalized within two weeks. On the other hand, a fine granular material persisted in the intercellular spaces. It is confirmed that the skin of the rhino mouse is a good model for the evaluation of the comedolytic effects of drugs. Moreover, it reveals the specific effects of retinoids on epidermal differentiation. We have demonstrated that topically applied CD271 induces modifications similar to those obtained with all-trans retinoic acid. It is thus concluded that CD271 is a potentially effective anti-acne agent.
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  • 46
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    Archives of dermatological research 283 (1991), S. 141-148 
    ISSN: 1432-069X
    Keywords: Sjögren ; Larsson syndrome ; Ichthyosis ; Ultrastructure ; Lamellar body ; Keratinization
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The ichthyosiform skin and the uninvolved skin of a 5-year-old Japanese female with Sjögren — Larsson syndrome were examined by light and electron microscopy to elucidate the keratinization disorder. Light microscopically, the epidermis of the ichthyosiform skin showed acanthosis, papillomatosis and hyperkeratosis. The horny cells had a basket-weave appearance. The granular cell layer was slightly thickened. Slight round cell infiltration and vascular dilatation were seen in the upper dermis. The uninvolved skin was histologically normal. Electron microscopically, in both ichthyosiform and uninolved skin, abnormal lamellar or membranous inclusions were present in the cytoplasm of horny cells of the epidermis. These inclusions appeared to be derived from some of the lamellar bodies and/or abnormal membranous structures found in the cytoplasm of spinous and granular cells. Mitochondria in the epidermal basal cells were more numerous in the ichthyosiform skin than in the uninvolved skin. These findings indicate that, whether the skin is involved or not, the epidermis of the patient with this disorder may always have a structural abnormality, which may be genetically determined. Local environmental factors may play a role in inducing the acanthosis and papillomatosis of the epidermis.
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  • 47
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    Development genes and evolution 199 (1991), S. 423-426 
    ISSN: 1432-041X
    Keywords: Oogenesis ; Accessory nuclei ; Developmental gradients ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary In the oocytes ofTenthredo olivacea, accessory nuclei (AN) are formed by budding from the nuclear envelope of the oocyte nucleus. Newly formed AN contain electron-dense material of nuclear origin and are surrounded by a double envelope devoid of pores. Such structures are subsequently transported to the peripheral ooplasm (periplasm), where they grow to reach a final diameter of 5 µm. In the envelopes of advanced AN nuclear pores arise. Through these pores “nuage” material is extruded into the surrounding periplasm. These findings are discussed with respect to a possible involvement of AN in the establishment of developmental gradients in hymenopteran oocytes.
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  • 48
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    Development genes and evolution 200 (1991), S. 77-85 
    ISSN: 1432-041X
    Keywords: Lysosomes ; Ultrastructure ; Chloroquine ; Blastocyst ; Mouse
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Mouse morulae are known to undergo cavitation as soon as some external cells have entered the sixth cell cycle (Garbutt et al. 1987). Since the early cytological features of cavitation are still unclear, we undertook a careful ultrastructural analysis of late morulae-nascent blastocysts. In addition, since maturation of lysosomes might be involved in the first step of cavity formation, we focused our attention on these organelles by means of the cytochemical localization of trimetaphosphatase activity and by the study of the effects of chloroquine on precavitation embryos. Our results suggest that cavitation starts in a few external cells (presumably competent cells entering the sixth cell cycle), by the chloroquine-sensitive formation of degradative autophagic vacuoles engulfing lipid droplets and vacuoles containing osmiophilic material. These complex structures enlarge (as a result of lipid metabolism?) and so transform into intrablastomeric cavities which, by means of a membrane fusion process, very rapidly become extracellular cavities that coalesce. The abembryonic pole of the blastocyst is determined in this way. Moreover, we suggest that the juxtacoelic cytoplasmic processes covering the inner cell mass (ICM) cells, which are known to restrict the expression of their totipotency during early cavitation (Fleming et al. 1984), are the latest remnants of the walls of the growing intrablastomeric cavities.
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  • 49
    ISSN: 1432-1106
    Keywords: Acetylcholine ; Fimbria/fornix ; Hippocampus ; Intracerebral grafts ; Muscarinic receptors ; Noradrenaline ; Phosphoinositides ; Serotonin ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Long Evans female rats sustained aspirative lesions of the septohippocampal pathways; subsequently, they received intrahippocampal suspension grafts of fetal septal-diagonal band or hippocampal tissue. The long term (8–10 months post-surgery) effects of these treatments were examined in the hippocampus for the following variables: concentration of hippocampal acetylcholine (ACh), muscarinic-stimulated (carbachol) formation of inositol monophosphate, accumulation of tritiated choline, noradrenaline (3H-NA) and serotonin (3H-5-HT), electrically evoked release of 3H-acetylcholine (3H-ACh), 3H-NA and 3H-5-HT, and choline acetyltransferase (ChAT) activity. The lesions decreased the levels of endogeneous ACh, the accumulation of 3H-choline and 3H-5-HT and the evoked release of both 3H-ACh and 3H-5-HT as well as the ChAT activity, but they failed to significantly affect the muscarinic-stimulated formation of inositol monophosphate and the accumulation and release of 3H-NA. Grafts of hippocampal cells were found to be ineffective on all lesion-induced effects. In contrast, grafts of septal-diagonal band origin attenuated the deficit of hippocampal concentrations of ACh and accumulation of 3H-choline without, however, improving release of 3H-ACh, accumulation and release of 3H-5-HT, and ChAT activity. These observations suggest that: (i) denervation-induced hippocampal muscarinic supersensitivity might not be long-lasting or the lesions, which in some cases spared the lateral edges of the fimbria, failed to induce any muscarinic supersensitivity, (ii) intrahippocampal grafts rich in cholinergic neurons do not foster recovery from the lesion-induced noncholinergic deficits we assessed, (iii) recovery of function may be expressed by some but not all biochemical or pharmacological cholinergic variables and (iv) graft-derived hippocampal reinnervation may be less efficient than the endogenous innervation of intact rats as indicated by the restoration of only some of the variables related to cholinergic function by intrahippocampal septal-diagonal band grafts.
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  • 50
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    Experimental brain research 84 (1991), S. 57-74 
    ISSN: 1432-1106
    Keywords: Hippocampal formation ; Neural networks ; HRP ; Tracing techniques ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary We used in vivo intracellular labeling with horseradish peroxidase in order to study the somadendritic morphology and axonal projections of rat entorhinal neurons. The cells responded to hippocampal stimulation with inhibitory postsynaptic potentials, and thus likely received direct or indirect hippocampal input. All cells (n = 24) showed extensive dendritic domains that extended in some cases for more than 1 mm. The dendrites of layer II neurons were largely restricted to layers I and II or layers I–III, while the dendrites of deeper cells could extend through all cortical layers. Computed 3D rotations showed that the basilar dendrites of deep pyramids extended roughly parallel to the cortical layering, and that they were mostly confined to the layer containing the soma and layers immediately adjacent. Total dendritic lengths averaged 9.8 mm ± 3.8 (SD), and ranged from 5 mm to more than 18 mm. Axonal processes could be visualized in 21 cells. Most of these showed axonal branching within the entorhinal cortex, sometimes extensive. Efferent axonal domains were reconstructed in detail in 3 layer II stellate cells. All 3 projected axons across the subicular complex to the dentate gyrus. One of these cells showed an extensive net-like axonal domain that also projected to several other structures, including the hippocampus proper, subicular complex, and the amygdalo-piriform transition area. The axons of layer III and IV cells projected to the angular bundle, where they continued in a rostral direction. In contrast to the layer II, III and IV cells, no efferent axonal branches leaving the entorhinal cortex could be visualized in 5 layer V neurons. The data indicate that entorhinal neurons can integrate input from a considerable volume of entorhinal cortex by virtue of their extensive dendritic domains, and provide a further basis for specifying the layers in which cells receive synaptic input. The extensive axonal branching pattern seen in most of the cells would support divergent propagation of their activity.
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  • 51
    ISSN: 1432-1106
    Keywords: 2-Aminophosphonopentanoate ; NMDA receptors ; Spatial learning ; Visual discrimination ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Chronic intraventricular infusion of the selective NMDA receptor antagonist AP5 appears to cause an impairment of spatial but not visual discrimination learning. However, Goddard (1986) has questioned whether this dissociation in task-selectivity reflects a difference in the underlying neural mechanisms or differential drug diffusion. Two experiments conducted to address this issue established (a) that chronic intraventricular infusion of AP5, at a dose sufficient to cause a spatial learning impairment, results in a relatively uniform distribution of the drug across the brain, and (b) that chronic bilateral intracortical infusion at sites very close to visual cortex also fails to impair visual discrimination learning. These findings argue against differential diffusion being a major cause of the sensitivity of spatial but not visual discrimination tasks to AP5, and raises the possibility that representational and procedural memory tasks may depend upon distinct cell-biological mechanisms of plasticity.
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  • 52
    ISSN: 1432-1106
    Keywords: Monoclonal antibody (mabQ113) ; Zebrin I ; Purkinje cells ; Spinocerebellar projections ; Central cervical nucleus ; Cholera toxin ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary We have examined the topographic relationship between the sagittal bands of zebrin I immunoreactive Purkinje cells revealed by a monoclonal antibody, mabQ113, and the distribution of spinocerebellar fibers originating from the central cervical nucleus in the rat. The mossy fiber terminals were anterogradely labeled following injections of cholera toxin subunit B into the C1–C3 segments and visualized immunohistochemically. Zebrin I positive Purkinje cells appeared in seven sagittal bands (P1+ to P7+ bands). In lobules I–V of the anterior lobe, labeled mossy fiber terminals were distributed in the midline region, subjacent to the P1+ bands and at around 0.5 mm from the midline region, subjacent to the P2+ band in the lateral A1 to the medial A2 zones of Voogd et al. (1985). Labeled terminals were seen in the entire B zone and those distributed in its medial part were related to the P3+ band. In lobule VIII, labeled terminals were seen subjacent to the P1+, P2+ and P3+ bands, which were located in the lateral A1–A3 (or B) zones. In the copula pyramidis, labeled terminals appeared subjacent to the P4+, P5+ and the P6+ bands in the C1 and C2 zones (or the C1-C3 zones). Although the labeled terminals were seen beneath the zebrin I positive bands, the borders of terminal distribution were not well-delineated, and did not respect the borders of zebrin I positive bands.
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  • 53
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    Experimental brain research 84 (1991), S. 142-158 
    ISSN: 1432-1106
    Keywords: Thalamic lesions ; Kainic acid ; HRP ; Callosal connections ; Laminar density ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The patterns of callosal interconnections between the visual cortices of rats display considerable plasticity in response to various neonatal manipulations. In the present study, many neurones in the principal visual thalamic relay nuclei, the dorsal lateral geniculate nucleus (DLG) and to a lesser extent those in the lateral posterior nucleus (LP) were destroyed by injections of the neurotoxin — kainic acid — on the first day of postnatal life. Four weeks later, as demonstrated with the anterograde and retrograde transport of the enzyme horseradish peroxidase (HRP) injected into the occipital lobe of one hemisphere, callosally projecting neurones and terminals were distributed more widely in the retinotopically organized areas 17, 18a and 18b of the visual cortex ipsilateral to the lesioned visual thalamus than in unoperated control animals of the same age. By contrast, in the visual cortex contralateral to the lesioned visual thalamus the areal distribution of callosally projecting neurones and terminals was similar to that of the controls, that is, largely but not exclusively restricted to the common border of areas 17 and 18a. Both in unoperated and operated animals, cells in lamina V of several cytoarchitectonically defined areas that are not retinotopically organized (area 8 in the frontal lobe, area 29d in the retrosplenial limbic cortex and perirhinal areas 35/13 in the temporal lobe) also project to contralateral visual cortices. In areas 8 and 29d, the total numbers, laminar distributions and densities of labelled callosal cells both ipsilateral and contralateral to the kainate-injected visual thalamus were similar to those in the controls. However, in the temporal lobe, the areal distribution of the labelled callosal neurones was more extensive than that in the controls and labelled cells in areas 35/13 of the cortex contralateral to the kainate-lesioned visual thalamus merged with those in the neighbouring areas 20 and 36. By contrast, the areal distribution of associational neurones in area 18a and in nonretinotopically organized areas projecting to area 17 were very similar in controls and in operated animals (neonatal kainate lesion of the visual thalamus, neonatal section of the corpus callosum or both procedures combined). However, in operated animals, the labelled associational neurones projecting from the supragranular laminae (II/III) of area 18a to area 17 constituted a higher proportion of all cells than did those in the unoperated control animals. Thus, overall the number of associational neurones projecting from area 18a to area 17 was slightly increased by the experimental manipulations performed. The implications of these results concerning the mechanism(s) underlying the developmental changes in the distribution of commissural and associational neurones projecting to the rat's visual cortex are discussed.
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  • 54
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    Experimental brain research 85 (1991), S. 324-334 
    ISSN: 1432-1106
    Keywords: HRP/WGA-HRP injections ; Retinotopically organized areas ; Thalamic afferents ; Laminar distribution of cortical afferent neurons ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Afferent connections of rat primary visual cortex (area 17 or V1 area) and the rostral and caudal parts of areas 18a and 18b were studied, by placing in each of the areas, small electrophoretic injections of enzyme horseradish peroxidase (HRP) or wheat germ agglutinated-HRP. The results indicate that: 1) each of the areas has a distinct pattern of distribution of afferent neurons in the ipsilateral visual thalamus — area 17 receives its principal thalamic input from the dorsal lateral geniculate nucleus, the caudal parts of areas 18a and 18b receive a major thalamic input from the lateral posterior nucleus and a minor input from the posterior nucleus, while the rostral parts of areas 18a and 18b receive a major input from the posterior nucleus, and a minor projection from the lateral posterior nucleus; 2) the rostral and caudal parts of areas 18a and 18b each receive an associational input from area 17; 3) the rostral parts of areas 18a and 18b each receive associational input from three different extrastriate regions, the caudal part of the same extrastriate area, and the rostral and caudal parts of the other extrastriate area, whereas the caudal parts of areas 18a and 18b receive associational inputs only from one or two extrastriate regions; 4) area 17, area 18b and rostral area 18a each receive a substantial associational input from lamina V of the caudal part of the frontal eye field (FEF) in the motor cortex; however the input from the FEF to caudal area 18a (if present) is very small; 5) The extrastriate areas studied receive associational input from the restrosplenial cingulate area 29d; however, the input from area 29d to area 17 appears to be very small. The distinct patterns of distribution of prosencephalic afferents suggest to us that multiple retinotopically organized areas described previously in the rat cortex (cf Montero 1981; Espinoza and Thomas 1983) represent functionally distinct areas.
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  • 55
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    Experimental brain research 85 (1991), S. 359-363 
    ISSN: 1432-1106
    Keywords: Dorsal raphe ; Paraventricular nucleus ; Serotonin ; Magnocellular neurons ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary In order to determine the responses of paraventricular nucleus magnocellular neurones following activation of central serotonergic pathways, single unit activity was recorded and responses following electrical stimulation of the midbrain dorsal raphe nucleus were examined. Approximately one third (32%) of the phasically active, vasopressin-secreting neurones were inhibited by the stimulation, the remaining such cells being nonresponsive. In contrast, only two of the non-phasic cells (13%) were inhibited by the stimulation whilst 53% were excited (p〈 0.005, chi2-test). The onset latency of both inhibitory and excitatory responses were similar, whilst offset of the inhibitory responses was about twice that of the excitatory responses (p 〈 0.005, t-test). Two of the nonphasic cells were antidromically identified as projecting to the dorsal raphe. The results obtained indicate a role for dorsal raphe projections to the paraventricular nucleus in the regulation of neurohypophysial hormone secretion. The observation that different sub-populations of the cells recorded showed different responses, suggests that several mechanisms may be involved in the control of neuronal activity in the region recorded, in response to activation of the central serotonergic pathway examined. The results obtained are intended to further clarify the neural mechanisms regulating the secretion of vasopressin and oxytocin from the neurohypophysis.
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  • 56
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    Experimental brain research 85 (1991), S. 501-506 
    ISSN: 1432-1106
    Keywords: Neural grafts ; Striatum ; Cocaine ; Immediate-early gene ; c-fos ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Cocaine, a catecholamine agonist, has been shown to produce a transient induction of the immediate-early gene c-fos and its protein product Fos in the striatum of normal rats. In the present study we report that the expression of Fos can be induced by cocaine challenge in intrastriatal grafts derived from cell suspensions of embryonic striatal primordia. Fos-like immunoreactivity in the nuclei of grafted neurons was detected 2 hr after the injection of 50 mg/kg cocaine into the host rats. Neurons with Fos-immunoreactive nuclei tended to form clusters in the striatal grafts. The Fos-rich clusters were aligned with acetylcholinesterase (AChE)-rich and tyrosine hydroxylase (TH)-rich patches demonstrated in adjoining sections. Previous studies have shown that presynaptic and postsynaptic cellular markers of the dopaminergic system in the striatum, including immunostaining for TH and dopamine- and adenosine 3′:5′-monophosphate-regulated phosphoprotein (DARPP-32), and binding for high affinity dopamine uptake sites and for dopamine D1 and D2 receptor sites, are all concentrated in the AChE-rich patch regions (P regions) of such embryonic striatal grafts. The preferential expression of Fos in neurons of the P regions of the grafts thus implies that the induction of Fos was cell-type specific in being concentrated in the parts of the grafts that express striatal phenotype and that are innervated by catecholamine-containing fibers. This specificity strongly suggests that the activation of Fos expression in neurons of the P regions of the grafts reflects dopaminergic interactions between the grafts and host nigrostriatal fibers. We conclude that the cellular messenger systems and transcriptional activation mechanisms responsive to dopaminergic stimulation by the host can be activated in the embryonic striatal grafts, and that the grafts are thus functionally integrated into the host brain at the level of cellular signaling systems.
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  • 57
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    Experimental brain research 85 (1991), S. 543-551 
    ISSN: 1432-1106
    Keywords: Voltage-dependent Ca2+-currents (HVA or L-type) ; Inactivation ; Intraneuronal Ca2+ ; Buffering ; Dentate gyrus granule cells ; Kindling-induced epilepsy ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Nerve cells that lack the cytoplasmic Ca2+ binding protein Calbindin-D28K (CaBP) appear to be selectively vulnerable to Ca2+-related injury consistent with a postulated intraneuronal Ca2+-buffering role of CaBP. We have confirmed the selective loss of CaBP from the dentate gyrus during kindling-induced epilepsy in acutely dissociated granule cells (GCs) from kindled rats. Immunohistochemically stained kindled neurons showed a significant loss of CaBP when compared to controls (p 〈 0.001; ANOVA). The Ca2+-buffering role of CaBP was assessed in acutely dissociated control and kindled GCs by examining a physiological process highly sensitive to intracellular Ca2+-buffering: the Ca2+ -dependent inactivation of high-voltage activated (HVA or L-type) Ca2+ currents in the absence (or presence) of exogenous Ca2+-chelators. Whole-cell patch clamp recordings in kindled GCs demonstrated a markedly enhanced Ca2+-dependent inactivation of Ca2+-currents. After brief conditioning Ca2+ currents, in the absence of an exogenous intraneuronal Ca2+-chelator, subsequent test Ca2+ currents were inactivated by 58.3% in kindled GCs, a significant increase from the 37.4% inactivation observed in control GCs (p〈 0.005; ANOVA). The differential Ca2+ current decay and Ca2+-dependent inactivation were prevented in both control and kindled GCs upon loading the neurons with the exogenous Ca2+-chelator BAPTA. These experiments demonstrate a high correlation between the loss of CaBP and changes in Ca2+ current inactivation and are consistent with the hypothesis that CaBP contributes to the physiological Ca2+-buffering in mammalian neurons.
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    Experimental brain research 85 (1991), S. 559-564 
    ISSN: 1432-1106
    Keywords: Thyroid hormone ; Development ; Hippocampus ; Dentate gyrus ; LTP ; Learning ; Memory ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Excess thyroid hormone at an early stage of development produces marked neurochemical and morphological alterations in the rat hippocampal formation. In order to better understand the functional significance of these changes, we tested adult rats treated neonatally with triiodothyronine (T3), and their control litter mates, in a spatial learning task and for the induction of longterm potentiation (LTP) in the dentate gyrus (DG) of the hippocampal formation. The T3-treated rats were significantly impaired in their performance on the spatial task in comparison to their matched controls. Similarly, the efficacy of LTP induction was significantly attenuated in the T3-treated animals. Further, a significant correlation was obtained between LTP induction and performance on the spatial learning task. Thus, a brief neonatal excess of thyroid hormone produces impairments in spatial learning along with decreases in LTP, long held as a model of learning and memory. This relationship provides a unique opportunity to study associations between behavioral, physiological, pharmacological and morphological processes intimately associated with the hippocampal formation
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  • 59
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    Experimental brain research 84 (1991), S. 224-228 
    ISSN: 1432-1106
    Keywords: Dihydropyridine ; Hippocampus ; Calcium channel ; Nootropic ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Intracellular recording in the in vitro hippocampal slice was utilized to examine the effects of nimodipine and nifedipine on CA1 pyramidal cell excitability. The excitatory postsynaptic potential (EPSP) elicited by a single stimulus in stratum radiatum was enhanced by nifedipine as evidenced by increases in EPSP amplitude, area and slope. Threshold for synaptically-evoked somatic action potentials was decreased following either nifedipine or nimodipine application, often resulting in spontaneous action potential activity. A secondary, late EPSP-like event appeared in the intracellular recordings during and following bath application of nimodipine, and was associated with burst-like activity in field potential recordings. In accordance with the hydrophobic nature of these compounds, extensive washout in normal Krebs' solution failed to reverse their effects, but nifedipine's actions were photolabile. These results indicate that dihydropyridines can enhance synaptic efficacy in the CA1 region of the hippocampus.
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  • 60
    ISSN: 1432-1106
    Keywords: Chronic inflammation ; Arthritic rat joints ; Joint capsule mechanoreceptors ; PGE2 ; Bradykinin ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The role of PGE2 in the sensitization of highthreshold tarsal joint mechanoreceptors (putative nociceptors) has been investigated in 11 arthritic and 16 normal rats. Injections of a low dose of Freund's complete adjuvant at multiple sites into the tissues surrounding the ankle joint induced a chronic unilateral monoarthritis in the injected limb. Measurements of both spontaneous activity and responses of tarsal joint mechanoreceptors to repeated graded mechanical stimuli were made. All of the mechanoreceptors examined had afferent fibres with conduction velocities in the C or A-δ range. Using this new model of joint inflammation we have shown that lysine acetylsalicylate reduces the mechanical sensitivity of these joint mechanoreceptors and reduces the spontaneous activity in afferent nerve fibres. Prostaglandin E2 is unable to restore either the spontaneous activity in the afferent axon or the mechanical sensitivity of tarsal joint mechanoreceptors after lysine acetylsalicylate in the arthritic rat. Similarly, PGE2 does not sensitize or excite tarsal joint mechanoreceptors in the normal rat. In the normal rat, however, PGE2 potentiates the excitatory action of bradykinin and enhances the sensitizing effect of bradykinin on the responses of joint mechanoreceptors to mechanical stimulation when both substances are injected simultaneously. These results indicate that PGE2 is not important in the sensitization of these joint mechanoreceptors in this model of chronic joint inflammation but that in other circumstances PGE2 may be able to contribute to a sensitization of joint mechanoreceptors by enhancing the action of bradykinin.
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  • 61
    ISSN: 1432-1106
    Keywords: 5-Hydroxytryptophan ; Parachlorophenylalanine ; Benserazide ; Sleep ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary In the rat, the insomnia which follows the administration of parachlorophenylalanine (p-CPA), a serotonin synthesis inhibitor, is transiently reversed either by intra-cisternal injection of L-5-HTP or by an associated injection of 5-HTP and an L-aromatic-aciddecarboxylase inhibitor (benserazide). Histochemical, immunohistochemical and chemical investigations showed that 5-HTP administration does not lead to a detectable increase in cerebral 5-HT. These findings suggest that the restoration of sleep after p-CPA treatment could be mediated by the central action of 5-HTP.
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  • 62
    ISSN: 1432-1106
    Keywords: Status epilepticus ; Pilocarpine ; Substantia nigra pars reticulata ; Astrocytes ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The substantia nigra has a gating function controlling the spread of epileptic seizure activity. Additionally, in models of prolonged status epilepticus the pars reticulata of substantia nigra (SNR) suffers from a massive lesion which may arise from a massive metabolic derangement and hyperexcitation developing in the activated SNR. In this study, status epilepticus was induced by systemic injection of pilocarpine in rats. The neuropathology of SNR was investigated using immunohistochemical techniques with the major emphasis on the time-course of changes in neurons and astrocytes. Animals surviving 20, 30, 40, 60 min, 2, 3, 6 hours, 1, 2, and 3 days after induction of status epilepticus were perfusion-fixed, and brains processed for immunohistochemical staining of SNR. Nissl-staining and antibodies against the neuron-specific calcium-binding protein, parvalbumin, served to detect neuronal damage in SNR. Antibodies against the astroglia-specific cytoskeletal protein, glial fibrillary acidic protein (GFAP), and against the glial calcium-binding protein, S-100 protein, were used to assess the status of astrocytes. Immunohistochemical staining for serum-albumin and immunoglobulins in brain tissue was taken as indicator of blood-brain barrier disturbances and vasogenic edema formation. Immunohistochemical staining indicated loss of GFAP-staining already at 30 min after induction of seizures in an oval focus situated in the center of SNR while sparing medial and lateral aspects. At 1 h there was additional vacuolation in S-100 protein staining. By 2 hours, parvalbumin-staining changed in the central SNR indicating neuronal damage, and Nissl-staining visualized some neuronal distortion. Staining for serum-proteins occurred in a patchy manner throughout the forebrain during the first hours. By 6 h, vasogenic edema covered the lesioned SNR. By 24 h, glial and neuronal markers indicated a massive lesion in the center of SNR. By 48–72 h, astrocytes surrounding the lesion increased in size, and polymorphic phagocytotic cells invaded the damaged area. In a further group of animals surviving 1 to 5 days, conventional paraffin-sections confirmed the neuronal and glial damage of SNR. Additional pathology of similar quality was found in the globus pallidus. Since astrocytes were always damaged in parallel with neurons in SNR it is proposed that the anatomical and functional interrelationship between neurons and astrocytes is particularly tight in SNR. Both cell elements may suffer in common from metabolic disturbance and neurotransmitter dysfunction as occur during massive status epilepticus.
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  • 63
    ISSN: 1432-1106
    Keywords: Chronic pain ; Plasticity ; Primary sensory neurons ; Nociception ; Image analysis ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Adjuvant-induced arthritis has been produced in adult rats in order to study the reorganization of serotonergic innervation in the spinal cord dorsal horn in a model of chronic pain. Immunocytochemical detection of CGRP and substance P was quantified with an image analyzer, and we found a transient increase for both peptides at 1 and 2 months, followed by a decrease to control levels after four months. At variance, quantification of serotonergic immunoreactivity showed a significant increase which persisted throughout the study. The significance of this finding is discussed with comparison of other experimental models involving reorganization of primary afferents to the spinal cord.
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  • 64
    ISSN: 1432-1106
    Keywords: Mossy fibers ; Perforant path ; (+)3-PPP ; Ditolylguanidine ; CNQX ; In vitro rat brain slice ; Neurotransmitter release ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Focal electrical stimulation of selected excitatory pathways in the hippocampal slice caused a decrease in the binding of [3H]-1,3-di(2-tolyl)guanidine (DTG) or [3H]-(+)-3-[hydroxyphenyl]-N-(1-propyl)piperidine ((3H)-(+)3-PPP) to haloperidol-sensitive sigma binding sites in the slice. Activation of the mossy fibers or perforant path by high frequency electrical stimulation caused the reduction in [3H]-DTG binding; whereas activation of fibers in the strata radiatum, lacunosummoleculare, alveus, or oriens did not affect [3H]-DTG binding. The decrease in binding observed was calcium-dependent and tetrodotoxin sensitive and varied with the frequency, intensity, and duration of stimulation. Although haloperidol-sensitive [3H]-DTG binding sites are distributed throughout the hippocampus, stimulation of the perforant path or mossy fibers resulted in a significant reduction in binding only in the dentate region of the slice. The decrease in binding following perforant path stimulation was blocked by the glutamate receptor antagonist 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX); whereas the decrease in binding caused by mossy fiber stimulation was not affected by CNQX or DL-APV. The results obtained support the hypothesis that activation of the granule cells in the hippocampal slice caused the release of an endogenous ligand which acts at the haloperidol-sensitive sigma binding site in the dentate gyrus.
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  • 65
    ISSN: 1432-1106
    Keywords: Superior colliculus ; Immunocytochemistry ; Serotonin ; Hamster ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Immunocytochemistry for serotonin (5-HT) was carried out in both hamsters and rats in order to determine whether or not 5-HT-positive cells existed in the superior colliculus (SC) of either species. In both hamster and rat, the superficial and deep SC laminae contained dense networks of 5-HT-positive fibers. The rat's SC contained no 5-HT-positive neurons. In hamster, numerous 5-HT-immunoreactive cells were visible throughout the depth of the stratum griseum superficiale (SGS). These neurons had a variety of morphological characteristics and included marginal cells, horizontal cells, and neurons with vertically oriented dendritic trees. No 5-HT-positive neurons were found in any other portion of the hamster's SC. 5-HT-positive SC cells were observed with antisera from two different sources and they were not seen in animals that were pretreated with reserpine. Pretreatment with fluoxetine (an inhibitor of 5-HT uptake) also resulted in a disappearance of 5-HT-positive neurons in the hamster's SC. This result indicated that “serotonergic” cells in the colliculus of this species are capable of taking up, but probably not synthesizing, this indoleamine. The dorsal and ventral lateral geniculate nuclei (LGNd and LGNv, respectively) both contain numerous 5-HT-positive fibers and both of these structures receive input from the SGS. Combination of retrograde tracing with fluorogold and immunocytochemistry indicated that 5-HT-accumulating SC neurons were not the source of these fibers. Unilateral ablation of the superficial SC laminae also failed to reduce 5-HT immunoreactivity in either the LGNd or LGNv. These results are consistent with the possibility that 5-HT-accumulating cells in the hamster's SC may be interneurons that take up this transmitter after it is released by afferents to this nucleus.
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  • 66
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    Experimental brain research 85 (1991), S. 621-624 
    ISSN: 1432-1106
    Keywords: Long-term depression ; Long-term potentiation ; Excitatory postsynaptic potentials ; NMDA receptors ; Prefrontal cortex ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary All the experiments were carried out in slices of rat prefrontal cortex maintained in vitro. The effect of 2-amino-5-phosphonovalerate (APV) was tested on the postsynaptic potential (PSP) recorded in layer V pyramidal cells, in response to single or high frequency stimulation of the superficial layers I–II. Wash-out of Mg2+ increased the amplitude and duration of the PSPs. This effect resulted from activation of N-methyl-D-aspartate (NMDA) receptors since it was suppressed by bath application of APV. Furthermore, in every cell tested in Mg2+ containing medium (N=16), exposure to APV reversibly reduced both mono- and polysynaptic components of the PSPs, indicating that, even in the control solution, activation of NMDA-coupled channels contributed to these synaptic events. Finally, the anomalous voltage-dependence of the EPSP in the presence of Mg2+ and its sensitivity to APV suggests that at least a fraction of the NMDA receptors are postsynaptically located. Tetanization was applied to the afferents of cells bathed in control- or APV-medium. Long-term potentiation (LTP) or long-term depression (LTD) is defined as an increase or a decrease respectively, of the PSPs peak amplitude or initial slope, lasting 20 min. In the control medium, LTP in synaptic efficacy was observed in 34% of the cells and LTD in 48% (N=23). When exposed to APV, none of the cells tested (N=16) showed LTP of the response. In contrast, the tetanus induced a LTD of the PSP amplitude or slope in 14 out of these 16 cells. The percentage of cells showing LTD in synaptic efficacy (87%) when the NMDA receptors activation was blocked was significantly higher than that in control-medium.
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  • 67
    ISSN: 1432-1106
    Keywords: Cyproterone ; Hypothalamus ; Pituitary ; Morphology ; Function ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Fetal exposure to cyproterone acetate (CPA), while allowing, normal sexual morphogenesis, has previously been shown to lead to functional endocrine abnormalities in adult rats of both sexes. Because of this, we examined morphologically and morphometrically the hypothalamic nuclei involved in sexual dimorphism as well as the pituitary lactotropes of rats exposed in utero from day 15 to 20 of gestation to CPA. Male and female offspring was studied at the age of 70–80 days. In both sexes the brain weight was lower (p〈0.05) in CPA-treated than in control rats. Morphometrical investigations showed that the surface density (Sv) and the volume density (Vv) of the ventromedial nucleus were higher (p〈0.05) in CPA-treated male than in control rats. By comparing sexes the Sv and Vv of the ventromedial nucleus were higher (p〈0.01) in CPA-treated male than in corresponding female rats. Also the nuclear surface of the tyrosine hydroxylase-immunoreactive neurons of the arcuate nucleus was higher (p〈0.05) in CPA-treated male than in female rats. In lactotropes of the pituitary gland the immunoreactive prolactin (PRL) was densitometrically increased (p〈 0.05) in CPA-treated female compared with control rats. By electron microscopy, PRL granules and autophagocytosis appeared to be more abundant in CPA-treated rats of both sexes. These data show that fetal exposure to CPA results in long-term anatomical and physiological alterations of hypothalamic and preoptic nuclei as well as of the pituitary lactotropes. These permanent changes support the functional endocrine abnormalities observed in adult rats.
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  • 68
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    Experimental brain research 83 (1991), S. 549-554 
    ISSN: 1432-1106
    Keywords: Beta-endorphin ; Formalin test ; Pain ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The involvement of the beta-endorphin (B-EP) system during acute prolonged (tonic) pain was investigated by biochemical and behavioral approaches in freely-moving rats after subcutaneous injection of a small amount of a dilute formaldehyde solution (0.08 ml, 5%) in a forepaw. Beta-endorphin-like immunoreactivity levels were increased over the respective control groups in rats killed 30, 60 and 120 min after injection in discrete regions of the rat brain, namely ventro-medial hypothalamus, ventro-basal thalamus and periaqueductal gray matter, and at 30 and 60 min in postero-medial thalamus. In a separate group of experiments a small amount of anti-B-EP or normal rabbit serum was injected in the lateral ventricle; 6 h later rats received formalin injection as in previous groups and their behavior was scored over the following 2 h. A significant hyperalgesia (as expressed by an increase in the amount of time rats spent licking or chewing the injected paw) was observed 10–50 min and 70–80 min after formalin in the anti-B-EP icv-injected group. Other behavioral parameters such as general motor activity, grooming and limb flexion were not different in the two groups, nor was animal behavior prior to formalin injection. Altogether these data suggest that the central beta-endorphin system is triggered by prolonged noxious stimulation in freely-moving animals, and in turn plays a physiological role in the modulation of the reaction to, or perception of, tonic pain.
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  • 69
    ISSN: 1432-1106
    Keywords: Dysthyroidism ; Neurochemical maturation ; Neurons ; Astrocytes ; Oligodendrocytes ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The effects of alteration of thyroid state on neurochemical maturation have been studied in rats made hypothyroid by daily injections of methimazole or hyperthyroid by daily supplementation with thyroid hormone (T3) from postnatal days 1 to 27. Biochemical assays on seven brain regions plus the spinal cord were carried out on 14 and 28 day-old rats as well as in adult rats after at least 40 days of recovery. 2′,3′cyclic nucleotide phosphohydrolase (CNPase), a specific marker for oligodendrocytes and myelination was significantly decreased in all regions except the spinal cord of hypothyroid rats. The astrocytic marker glutamine synthetase (GS) was slightly increased in the hippocampus of hypothyroid rats. Choline acetyltransferase (ChAT), a specific marker for cholinergic neurons, was decreased in the prefrontal and visual cortices, the striatum and the superior colliculus and increased in the cerebellum of hypothyroid rats; in addition, the enzyme activity was increased in the prefrontal cortex and striatum and decreased in the cerebellum of hyperthyroid rats. Acetyl-cholinesterase (AChE) activity was decreased in the prefrontal cortex and in the striatum of hypothyroid rats while 3H-quinuclidynil benzilate (QNB) muscarinic binding was decreased in all cortical areas and in the hippocampus of hypothyroid rats. Glutamate decarboxylase (GAD), a specific marker for GABAergic neurons, was decreased in the cortical areas of hypothyroid rats. Aromatic amino acid decarboxylase (AAD), a general marker for monoaminergic neurons, was unaffected. Alteration of neurochemical parameters was never observed in the spinal cord. Under our experimental conditions, the effects of alteration of thyroid state appeared graded and selective with respect to temporal, regional and cellular parameters.
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  • 70
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    Experimental brain research 87 (1991), S. 363-370 
    ISSN: 1432-1106
    Keywords: Visceral neuropathy ; Acrylamide ; Neurofilaments ; Neurofilament proteins ; Autonomic nerves ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary A variety of visceral nerves were studied by intermediate filament immunocytochemistry in rats intoxicated with acrylamide. In such animals, oesophageal and diaphragmatic motor end-plates were invaded and deformed by neurofilament protein-like material, while afferent fibres of diaphragmatic neuromuscular spindles and myelinated sensory fibres of the iris showed striking terminal accumulation of similar material. Conversely, the rich population of thin afferent fibres of the iris showed no obvious abnormality, while pre-terminal changes were seen along the extrinsic nerve fibres supplying the cornea and myenteric ganglia. Multiple lesions were demonstrated in gut nerves of acrylamide-treated rats, while scattered “enteric glial cells” showed abnormally coarse morphology and a striking increase in glial fibrillary acidic protein immunoreactivity. A distinct, delicately varicose appearence was revealed by neurofilament protein-immunostaining in bladder nerve fibres of normal rats, which was changed to one of coarse dilations by acrylamide. In conclusion, apparently selective changes were found along different types of axons, in dicating marked heterogeneity in cytoskeletal organisation among visceral nerves. Taken together with the proposed inhibition by acrylamide of neurofilament proteins degradation, the above findings may suggest a non-uniform distribution of neurofilament degradation sites along distal regions of different axons.
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  • 71
    ISSN: 1432-1106
    Keywords: Cutaneous nerve projections ; Dorsal horn ; Clarke's column ; Choleragenoid ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The aim of the present study has been to investigate the spinal projections of cutaneous hindlimb afferents particularly to the deep dorsal horn and to Clarke's column (CC), by using the B-subunit of cholera toxin conjugated to horseradish peroxidase. Injections into three different cutaneous hindlimb nerves in adult rats resulted in dense labeling in the dorsal horn laminae IIi-IV/V, moderate labeling in lamina I and modest labeling in dorsomedial parts of CC. Footpad injections gave similar results, except for a lack of labeling in CC and only weak labeling in laminae I and V. The results suggest that B-HRP should be a useful marker for studying cutaneous myelinated nerve fiber projections to the rat spinal cord.
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  • 72
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    Experimental brain research 84 (1991), S. 91-101 
    ISSN: 1432-1106
    Keywords: Ischemia ; Hyperglycemia ; Hypothermia ; Seizures ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Preischemic hyperglycemia aggravates brain damage following transient ischemia, and adds some special features to the damage incurred, notably a high frequency of postischemic seizures, cellular edema, and affectation of additional brain structures, such as the substanta nigra pars reticulata (SNPR). We raised the question whether mild intra-ischemic hypothermia (32–33° C), known to reduce selective neuronal vulnerability in normoglycemic subjects, also ameliorates the characteristic damage observed in hyperglycemic animals. To that end, two series of experiments were performed. In the first, normo- and hypothermic animals were subjected to 10 min of ischemia during hyperglycemic conditions (plasma glucose 20–25 mmol · 1-1), and allowed either 15 h or 1 week of recovery. In the second, both normo- and hyperglycemic animals were subjected to 15 min of ischemia (at normal or reduced temperature) and surviving animals were studied after 1 week of recovery. All normothermic, hyperglycemic animals developed postischemic seizures and died within the first 24 h. Mild hypothermia afforded substantial protection. Thus, 6/7 hypothermic animals subjected to 10 min of ischemia survived 1 week of recovery and none developed postischemic seizures. Of the hypothermic animals subjected to 15 min of ischemia 6/11 survived for 1 week, only one of which developed seizures. Protection by hypothermia was also shown by the histopathological analysis. Experiments with 10 min of ischemia and 15 h of recovery showed the expected damage in normothermic, hyperglycemic subjects. Hypothermia markedly reduced damage in all vulnerable structures, including the cingulate cortex and SNPR. The protection was most pronounced in the caudoputamen, where no affected neurons were seen in the hypothermic subjects. The experiments with 15 min of ischemia confirmed previous findings that mild hypothermia protects normoglycemic animals against the insult. The results also showed that hypothermia prevented most of the exaggeration of damage caused by hyperglycemia. However, under hypothermic conditions hyperglycemia still augmented damage in the cingulate cortex, medial and lateral venteroposterior thalamic nuclei, and SNPR, structures specifically damaged under hyperglycemic, normothermic conditions. This suggests that hypothermia has less of a protective effect on mechanisms causing such damage than on neuronal damage in the classic selectively vulnerable regions, particularly the caudoputamen.
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  • 73
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    Experimental brain research 84 (1991), S. 159-166 
    ISSN: 1432-1106
    Keywords: Plasticity ; Reactive synaptogenesis ; Inhibition ; Somatotopy ; Single units ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The present experiments were designed to determine the effects of removing the dorsal column nuclei on the evoked responses of the ventroposterolateral nucleus (VPL) neurons in the rat. Previously, we have observed inhibitory interactions between forelimb and hindlimb inputs to VPL (Roberts and Wells 1990), and have also observed a synaptic recovery process within VPL following dorsal column nuclei (DCN) lesions (Wells and Tripp 1987). In an attempt to describe any changes in VPL responses that correlate with the synaptic recovery in VPL following lesions to the DCN, we have studied the incidence of the inhibition process in VPL, the latency of activation of single unit VPL responses to peripheral nerve stimulation, the number of evoked unit responses observed per track studied and the somatotopy of responses in VPL. Dorsal column nuclei lesions did not alter the incidence or duration of the inhibitory interaction between forelimb and hindlimb inputs to VPL. Following DCN lesions, there was a significant increase in the latency to activation of VPL neurons by both forelimb and hindlimb inputs. This increase in latency returned to a non-significant difference from control over the same interval of time that is required for the structural recovery in VPL. There was a significant reduction in the number of evoked unit responses observed per track studied in the deafferented group at the twenty day post-lesion time course. This difference was no longer statistically significant in the sixty-four day post-lesion group. Finally, we have observed little change in the overall anatomic distribution of responses to forelimb or hindlimb stimulation in VPL following DCN lesions. This distribution is not discretely somatotopic when evoked by electrical stimulation of peripheral nerves either prior to or following DCN lesioning.
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  • 74
    ISSN: 1432-1106
    Keywords: Superior cervical ganglion ; Intraocular ; Transplants ; Tyrosine hydroxylase ; Neuropeptide Y ; Enkephalin ; Calcitonin gene-related peptide ; Neuro-peptide-‘like immunoreactivity’ ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The purpose of the present study was to investigate the viability, growth characteristics and neuropeptide expression of intraocular superior cervical ganglia (SCG) grafts from neonatal (1–3 d), mature (4–5 months) and aged (20–24 months) rats. In vivo measurements, Falck-Hillarp histochemistry using iris whole mounts to assess catecholamine fiber outgrowth and immuno-cytochemical localization of tyrosine hydroxylase (TH-), neuropeptide Y (NPY-), leu-enkephalin (ENK-) and calcitonin gene-related peptide (CGRP-) like immuno-reactivity (LI) were used. Measurements indicated a marked decrease in volume during the first week after grafting and a more gradual decrease thereafter. This was most evident in newborn SCG. With prolonged survival time, the newborn ganglia demonstrated more varicose nerve terminals and increased catecholamine fiber outgrowth and arborization. Extensive and complex outgrowth of catecholamine fibers with varicose nerve terminals occurred more rapidly with mature and aged ganglia. In situ, all ganglion cell bodies and fibers demonstrated TH-LI. Localization of TH-LI after grafting indicated an increase in fiber density and a decrease in cell body density of 65%, 40% and 40% in newborn, mature and aged ganglia respectively. NPY-LI in cell bodies had a perinuclear fluorescence pattern consistent with localization in the Golgi apparatus. Grafting of newborn, mature and aged SCG resulted in a 20%, 20% and 35% decrease respectively of cell bodies containing NPY-LI. A concommitant increase in fiber diameter, fluorescence intensity and extent of arborization was observed. The characteristic distribution of ENK-LI in cell bodies and axons in mature and aged ganglia was not affected by grafting. However, there was a greater than 50% reduction in the number of cell bodies expressing ENK-LI. CGRP-LI, localized in fibers and axon terminals in SCG in situ, was not identified after grafting. In summary, we have demonstrated that SCG from all age groups form extensive fiber networks and continue neuropeptide expression after intraocular grafting. This was seen best in mature and aged donors and may suggest a role for SCG transplants in the replacement of monoaminergic neurons in the CNS.
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  • 75
    ISSN: 1432-1106
    Keywords: Sleep ; Stress ; Pain ; Serotonin (5-HT) ; 5-hydroxyindoleacetic acid (5-HIAA) ; Monoamine oxidase inhibitors (MAOI) ; Voltammetry ; High pressure liquid chromatography (HPLC) ; Raphe dorsalis (n.RD) ; Hypothalamus ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary In the present work, voltammetric method combined with polygraphic recordings were used in animals under long-term chronic conditions; the extracellular concentrations of 5-hydroxyindole compounds (5-OHles) and in particular 5-hydroxyindoleacetic acid (5-HIAA) were measured in the hypothalamus and in the nucleus Raphe Dorsalis (n.RD). The hypothesis that extracellular detection of 5-HIAA, in animals under physiological conditions, might reflect serotonin (5-HT) release is suggested by the following observations: — serotoninergic neurons are reported to contain only monoamine oxidase type B (MAO-B); — an inhibitor of such an enzyme, MDL 72145 (1 mg/kg), fails to decrease the extracellular 5-HIAA peak 3 height; — MAO type A is contained in non-5-HT cells or neurons; — only the inhibitor of this last type of enzyme (Clorgyline 2.5 mg/kg) induces a complete disappearance of the voltammetric signal. The 5-HIAA measured in the extracellular space thus comes from the 5-HT released and metabolized outside the 5-HT neurons. Throughout the sleep-waking cycle, 5-OHles release occurs following two different modes: 1 — during sleep, in the vicinity of the 5-HT cellular bodies in the n.RD; this release might come from dendrites and be responsible for the 5-HT neuronal inhibition occurring during sleep; 2 — during waking, at the level of the axonal nerve endings impinging on the hypothalamus; this release might be related to the synthesis of “hypnogenic factors”. Finally, we have observed that in the hypothalamus, 30 min. of immobilization-stress (IS) induces a larger increase of the voltammetric signal (+ 80%) than a painful stimulation of the same duration (+ 30%); the possible link between the 5-OHles release occurring in this area during an IS and the subsequent paradoxical sleep rebound is discussed.
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  • 76
    ISSN: 1432-1106
    Keywords: Neural stimuli ; Paraventricular nucleus ; Corticotropin-releasing factor ; Serotonin ; 5,7-dihydroxytryptamine ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary In view of the role of serotonin in adrenocortical regulation, the effects of depletion of hypothalamic serotonin, using localized injections of the neurotoxin 5,7-dihydroxytryptamine into the hypothalamic paraventricular nucleus, on the rise in plasma corticosterone following afferent neural stimulation, were studied. The neurotoxin caused a significant reduction (p〈0.001) in hypothalamic serotonin content of about 50% during the first month and about 30% up to two months later. Basal and ether stress-induced rises in plasma corticosterone levels were unaffected at all times after this treatment, but responses to stimulation of the sciatic nerve were reduced for up to four weeks (p〈0.01), recovering at later times. Responses to photic and acoustic stimuli were almost entirely prevented up to four weeks following the treatment (p〈0.001) but showed a gradual recovery to full, or almost full, adrenocortical responses at eight weeks, following acoustic and photic stimulation respectively. These results demonstrate a differential recovery of the adrenocortical responses, following the neurotoxin injection and indicate that different neural modalities require different 5-HT concentrations in the PVN for the expression of a full adrenocortical response.
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  • 77
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    Experimental brain research 84 (1991), S. 487-494 
    ISSN: 1432-1106
    Keywords: Paraventricular nucleus ; Vagal afferents ; Gastric distension ; Vasopressin neuron ; Oxytocin neuron ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Extracellular recordings were made from vasopressin (AVP) and oxytocin (OXT)-secreting cells in the paraventricular nucleus (PVN) of the hypothalamus in rats anesthetized with urethane-chloralose to determine the effects of electrical stimulation of vagal gastric nerves and gastric distension on their activity. Electrical stimulation of gastric branches of the vagus nerves inhibited 5 and excited 10 of 32 phasically firing neurosecretory cells. Approximately one third of the phasically firing neuro-secretory cells (9 out of 29 cells) were transiently inhibited by gastric distension; an effect which was completely abolished by bilateral cervical vagotomy. In contrast, gastric nerve stimulation excited 45 of 72 non-phasically firing paraventricular cells. Thirteen of 77 non-phasically firing cells tested were excited by gastric distension. We conclude that there are some sensory afferent inputs originating from gastric receptors and transmitted by gastric vagal afferents which inhibit the activity of AVP- secreting neurons in the PVN although other inputs excite the cells. Similar inputs also excite some of the putative OXT-secreting neurons in the PVN.
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  • 78
    ISSN: 1432-1106
    Keywords: Cerebral ischemia ; Calbindin-D28K ; Parvalbumin ; retrograde axonal tracing ; CNS repair ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Cerebral ischemia can be caused by many diverse conditions such as cardiac arrest and severe hypotension and is often the cause of secondary brain damage following head injury or infantile birth trauma. The inadequate cerebral blood flow can result in permanent loss of essential brain circuitries and neurological deficits. The CA1 region of the hippocampal formation is the region of the brain that is most often lesioned following transient forebrain ischemia and is associated with impairments of learning and memory. Furthermore, the loss of such a large target area can lead to detrimental post-trauma synaptic reorganization. Since methods are not currently available for the prevention of neuronal loss following cerebral ischemia, a number of anatomical methodologies were utilized to investigate whether transplanted neurons had the potential to afford some measure of repair. The hippocampal CA1 region of the rat brain was lesioned by transient forebrain ischemia and subsequently repopulated with suspensions of fetal hippocampal tissue. The ability of the transplanted neurons to remain viable when placed into a degenerating environment was confirmed by the histological demonstration of 3H-thymidine labelled neurons in the lesioned region. Histological and immunohistochemical techniques showed that the transplanted neurons developed cytological features that were indistinguishable from their normal CA1 counterparts, often showed a remarkable degree of organization, and expressed some of the same neuron specific proteins; specifically calbindin-D28K and parvalbumin. Acetylcholinesterase histochemistry and retrograde axonal transport of Fluorogold demonstrated that some afferent and efferent fibre projections to and from the septal nucleus could be reinstated. The data have shown that the transplanted neurons can demonstrate many of the anatomical properties that are characteristic of the adult cells they have replaced and therefore have great potential for the reconstruction of severe focal lesions due to ischemia.
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  • 79
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    Experimental brain research 86 (1991), S. 555-561 
    ISSN: 1432-1106
    Keywords: Cerebral ischemia ; Noradrenaline ; Desipramine ; Idazoxan ; Microdialysis ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Using microdialysis, extracellular noradrenaline (NA) levels in the rat cerebral cortex were studied under isoflurane/N2O anaesthesia before, during and for 6 hours following 10 min of forebrain ischemia in a 2-vessel occlusion model. A microdialysis probe was introduced into the parietal cortex and dorsal hippocampus in anaesthetized rats and continuously perfused with Krebs-Ringerbicarbonate buffer with or without the NA uptake inhibitor desipramine (DMI, 5 μM). Twenty min fractions were collected and the extracellular NA levels were measured in the dialysates using HPLC with electrochemical detection. The basal NA concentration in the dialysate was 10.5±1.8 (mean±SEM) pg/20 min fraction and increased to 39.3±4.8 pg/20 min fraction after local administration of DMI. During ischemia, NA increased to 38 times the basal level without DMI, and 6 times with DMI included during two hours' perfusion prior to ischemia. After recirculation NA levels returned to, or even transiently decreased below, preischemic values. With DMI present in the dialysis buffer, administration of idazoxan immediately following ischemia delayed the return to preischemic NA levels in the recirculation phase. In the absence of DMI, no effect of idazoxan on postischemic levels of NA was found. Local administration of DMI increases basal extracellular NA levels and reduces the ischemia-induced NA release. The latter effect may be a due to inhibition of the NA uptake system working in a reversed mode, or as a result of decreased synthesis of NA due to activation of presynaptic α2-receptors by the increased synaptic NA levels. Postischemic treatment with the α2-adrenoceptor antagonist idazoxan in combination with DMI prolongs the period of elevated extracellular NA levels, which may be of importance for the protective properties of idazoxan against ischemic cell injury.
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  • 80
    ISSN: 1432-1106
    Keywords: Degeneration ; Retina ; Electroretinogram ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary A lesion to the optic nerve of adult mammals leads to the retrograde degeneration and finally to the death of injured retinal ganglion cells. In this study, we have evaluated the effects induced by different sites of axotomy on the functional changes occurring in the retinal ganglion cells after optic nerve section. We have investigated the functional properties of retinal ganglion cells of adult rats by recording the retinal responses to patterned stimuli (pattern electroretinogram) after unilateral section of the optic nerve at two different levels: intraorbital and intracranial. The results show that the site of lesion of the optic nerve affects the time of disappearance of the pattern electroretinogram. The pattern electroretinogram takes longer to be degraded after an intracranial section than an intraorbital section.
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  • 81
    ISSN: 1432-1106
    Keywords: Luteinizing hormone-releasing hormone ; Gamma-aminobutyric acid ; In situ hybridization ; Immunocytochemistry ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Gamma-aminobutyric acid (GABA) is thought to play an important role in the regulation of luteinizing hormone-releasing hormone (LHRH) release but its role in the regulation of LHRH gene expression and LHRH synthesis is not known. We hypothesized that since GABA appears to have primarily inhibitory effects on LHRH cells (at the level of the cell body), GABA may act to decrease LHRH gene expression and peptide synthesis. This hypothesis was tested by examining the effect of GABA receptor activation and GABA receptor blockade on LHRH mRNA and peptide levels employing in situ hybridization and immunocytochemistry. Cells in the preoptic area (POA) of ovariectomized (ovx) rats were selectively exposed in vivo to specific GABA-ergic receptor agonists or an antagonist for up to 24 h. THIP, a specific GABA a receptor agonist, did not have a significant effect on either the intensity of LHRH immunoreactivity, or the number of LHRH-ir cells, observed as compared to controls. Baclofen, a GABA b receptor agonist appeared to decrease the number of cells with the greatest intensity of LHRH immunoreactivity, compared to controls. In situ hybridization, with either a tritiated RNA probe or a 32P-labelled oligonucleotide, complementary to LHRH mRNA, revealed that THIP either had no effect on the labelling intensity (32P-labelled oligonucleotide) or (contrary to our hypothesis) a slight excitatory effect on the level of LHRH mRNA detected per cell (tritiated RNA probe). Bicuculline (a specific GABA a receptor antagonist) decreased both the number of labelled cells observed per section through the POA, and the intensity of labelling observed in sections hybridized with the 32P-labelled oligonucleotide. These results suggest that in the POA GABA a receptors do not exert an inhibitory effect on LHRH gene expresssion, but rather could affect LH perhaps by electrically inhibiting LHRH neurons. In contrast, baclofen appeared to exert an inhibitory effect on LHRH gene expression, since the number of grains per labelled cell in the POA of baclofen treated rats was lower than the grains per labelled cell of control rats. Also, similar to the results obtained with immunocytochemistry, in situ hybridization following baclofen treatment suggested that activation of GABA b receptors is able to reduce the number of neurons with the highest levels of LHRH mRNA. Thus, in the POA, GABA acting through GABA b receptors could be effective through changes in mRNA or peptide synthesis.
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  • 82
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    Experimental brain research 85 (1991), S. 537-542 
    ISSN: 1432-1106
    Keywords: Generators ; Brainstem auditory evoked potentials ; Stereotaxic radiofrequency coagulation ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The generators of brainstem auditory evoked potentials (BAEPs) in rats were investigated experimentally. Discrete lesions of the brainstem auditory pathway were made unilaterally using a stereotaxic radiofrequency coagulation method, and the BAEPs were recorded before and after the lesions to observe the alterations. The waves of the BAEPs were affected by the lesions as follows: (1) all of the BAEP waves were attenuated or eliminated by a lesion of the auditory nerve; (2) wave II was abolished or attenuated in amplitude following a lesion of the cochlear nucleus; (3) marked reduction or abolition of wave III occurred with some effect on waves IV and V following lesions of the superior olivary complex; (4) the following trough in the wave III was significantly attenuated by lesions of the lateral lemniscus that were associated with inconsistent changes in waves IV and V; (5) no waves were affected significantly by a lesion of the inferior colliculus. The method of radiofrequency lesion using stereotaxic localization proved to be a simpler and more rapid procedure for determining the generators of BAEPs in animals than other surgical lesion methods.
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  • 83
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    Experimental brain research 85 (1991), S. 577-586 
    ISSN: 1432-1106
    Keywords: Acoustic thalamus ; Amygdala ; Emotional memories ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Projections from the acoustic thalamus to the lateral nucleus of the amygdala (AL) have been implicated in the formation of emotional memories. In order to begin elucidating the cellular basis of emotional learning in this pathway, the ultrastructure and synaptic associations of acoustic thalamus efferents terminating in AL were studied using wheat-germ agglutinated horse-radish peroxidase (WGA-HRP) and Phaseolus vulgaris Leucoagglutinin (Pha-L) as ultrastructural anterograde axonal markers. The tracers were injected into those areas of the thalamus (medial division of the medial geniculate body and posterior intralaminar nucleus, MGM/PIN) known both to project to AL and to receive afferents from the inferior colliculus. Terminals labeled with WGA-HRP or Pha-L in AL contained mitochrondria and many small, round clear vesicles and 0–3 large, dense-core vesicles. Most labeled terminals formed asymmetric synapses on unlabeled dendrites; of these the majority were on dendritic spines. These data demonstrate that projections from the acoustic thalamus form synapses in AL and provide the first characterization of the ultrastructure and synaptic associations of sensory afferent projections to the amygdala.
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  • 84
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    Experimental brain research 87 (1991), S. 223-226 
    ISSN: 1432-1106
    Keywords: Globus pallidus ; Inferior colliculus ; Retrograde fluorescent tracer ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary After injection of fluorescent tracer into the inferior colliculus (IC), retrogradely labeled cells were observed not only in the temporoauditory cortex (ACx) and the substantia nigra pars lateralis, but also in the globus pallidus (GP). These labeled GP cells were localized exclusively in the caudal portion of the GP, which has been known to project to the ACx. Employing a retrograde fluorescent double labeling technique, the GP-IC neurons were found to be distributed in a separate manner from the GP-ACx neurons within the caudal GP. The present study provides further anatomical evidence that the caudal GP has a functional role in auditory processing.
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  • 85
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    Experimental brain research 87 (1991), S. 245-253 
    ISSN: 1432-1106
    Keywords: Thalamus ; VL neurons ; Cerebellum ; Intracellular recording ; Biocytin ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Intracellular recordings from thalamic neurons receiving cerebellar inputs were performed under urethane anesthesia in the rat. A total of 64 neurons were recorded intracellularly with micropipettes filled with 4% biocytin solution (dissolved in 0.5 M K-acetate), and cerebellar-induced EPSPs (CN-EPSPs), the membrane resistance and firing properties were analyzed with intracellular current injections. The mean latency of CN-EPSPs was 1.9 ± 0.8 ms and the mean input resistance measured in 10 neurons was 17.6 ± 5.0 MΩ. Thirty-two out of 35 stained neurons were analysed morphologically; 28 of these neurons were located in the VL, and 26 received CN-EPSPs. Their somata were round or polygonal in shape and the mean size was 22.5 × 15.2 μm. They had radially extending spinous dendrites, and the mean radii of the dendritic fields were 214.7 μm in the frontal and 171.4 μm in the sagittal planes. These morphological features were similar to those observed in the sensory relay nucleus of the thalamus.
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  • 86
    ISSN: 1432-1106
    Keywords: Explants ; Basal ganglia ; Substantia nigra ; Dopamine ; Ventral mesencephalon ; Neural development ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Organotypic slice cultures of striatum and neocortex were prepared from newborn to seven day old rats and cultured for three to 60 days. When processed for tyrosine hydroxylase (TH) immunocytochemistry medium-sized, aspiny TH immunoreactive (TH-i) neurons with a similar morphology were revealed in the striatum and the neocortex. The neurons had a very similar morphology in both tissues and were present both when the two tissues were grown separately as single cultures and when grown together either en bloc as part of the same tissue slices or as co-cultures. In order to examine whether innervation by dopaminergic fibers would affect the expression of TH-i neurons in the striatal slice cultures, co-cultures of ventral mesencephalon (VM) and striatum were prepared, but the ingrowth of TH-i fibers from the VM did not alter the expression of TH immunoreactivity by a subpopulation of striatal neurons.
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  • 87
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    Experimental brain research 83 (1991), S. 598-606 
    ISSN: 1432-1106
    Keywords: Frequency modulation ; Inferior colliculus ; Click-sensitive units ; Receptive space ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The response of 835 click-sensitive neurons in the inferior colliculus (IC) to ramp frequency modulated (FM) tones was studied in the anaesthetized rat. More than 70% of the cells were sensitive to the FM sound, and over 25% were “FM specialized”. Systematic variations of the stimulus parameters showed that sweep velocity, sweep range, and intensity of the FM signal were the 3 basic determinants for the unit response. For an“FM specialized” cell, the response pattern to each of the parameters was either monotonic or bell-shaped. The population statistics of response patterns to the FM parameters, including the tuning factors, were generated. A stimulus domain was proposed to represent the“receptive space” of the FM cells.
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  • 88
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    Experimental brain research 84 (1991), S. 303-310 
    ISSN: 1432-1106
    Keywords: Huntington's disease ; Quinolinic acid ; Striatum ; Behavior ; Transplantation ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Quinolinic acid (QA) and related excitotoxins produce a pattern of neuronal loss and neurochemical changes in the rat striatum similar to that of patients suffering from Huntington's disease, suggesting neurotoxicity is important in the etiology of that disease. Thus, strategies for limiting excitotoxin-induced striatal damage, like that caused by QA, may be of great benefit to these individuals. Accordingly, we tested the ability of both neural and non-neural tissue implants to protect the rat striatum against a subsequent QA challenge. Our results demonstrated that recipients of fetal striatal grafts were significantly less affected by striatal injections of QA than non-grafted animals. In contrast to the latter, fetal striatal tissue recipients did not exhibit apomorphine-induced rotation behavior and showed a sparing of cholinergic and enkephalinergic systems normally lost following QA injections. Animals grafted with adult rat sciatic nerve, adrenal medulla or adipose tissue all showed a less dramatic behavioral protection and sparing of cholinergic and enkephalinergic systems. These results suggest that fetal striatal tissue exerts an optimal, and perhaps specific protective influence on the host brain.
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  • 89
    ISSN: 1432-1106
    Keywords: Ischemia ; GABA ; Autoradiography ; Microdialysis ; In vitro electrophysiology ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary We have investigated the GABAergic system in rat hippocampus at 1 hour and up to 21 days following 20 min of global cerebral ischemia. Distribution of 3H-GABA (in excess of unlabeled baclofen) and 3H-Ro-15-1788 (benzodiazepine antagonist) binding sites in hippocampus was studied utilizing quantitative autoradiography. The 3H-GABA binding was unchanged (p〉 0.01) after ischemia, whereas the 3H-Ro-15-1788 binding decreased significantly (p〈 0.01) in all hippocampal subfields 1–21 days after ischemia. Using microdialysis in CA1, we found that K+-stimulated GABA release at 1 hour and 1 day after ischemia was unchanged (p〉 0.01) in comparison to preischemic controls. Electrophysiological recordings were made from CA1 of hippocampal slices prepared from rats sacrificed 1 hour, 1 day and 2 days after ischemia. Field potentials evoked by stimulation of the Schaffer collaterals showed no differences (p 〉 0.01) from those taken from controls. Postischemic intracellular recordings from the CA1 pyramidal cells showed that fast and slow inhibitory postsynaptic potentials were readily evoked on orthodromic stimulation. Together with our previous morphological results, demonstrating survival of hippocampal interneurons following ischemia, we conclude that hippocampal GABAergic interneurons preserve their inhibitory potential in the period preceding delayed CA1 pyramidal cell death. This conclusion taken together with the observation that postischemic 3H-Ro-15-1788 binding in hippocampus declined, suggest that benzodiazepines (by increasing the receptor affinity), GABA analogs, and GABA uptake inhibitors may be usefull in the treatment of ischemic CA1 pyramidal cell death in the rat.
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  • 90
    ISSN: 1432-1106
    Keywords: Hypothalamic paraventricular nucleus ; PHA-L ; Spinal projection ; Sympathetic preganglionic neurons ; Dendritic organization ; Cholera toxin ; Immunohistochemistry ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The descending projection of the hypothalamic paraventricular nucleus (PVN) to the sympathetic preganglionic neurons (SPNs) in the upper thoracic cord of the rat was studied. PVN-fibers were labeled by anterograde transport of Phaseolus vulgaris leucoagglutinin (PHA-L), while SPNs were retrogradely labeled with cholera toxin subunit B (CTb) which was injected into the superior cervical ganglion. SPNs labeled with CTb were mainly observed in the nucleus intermediolateralis (IML) pars principalis and pars funicularis, and a small number of them were in the nucleus intercalatus (IC) and central autonomic nucleus (CA). SPNs found in the IML had dendrites that projected in various directions. Five types of dendritic projections were noted: medial, rostral, caudal, lateral (including dorsolateral) and ventral. Longitudinal dendritic bundles interconnected each cell cluster in the IML. Medial dendrites of the IML, together with dendrites of the IC and CA, formed transverse dendritic bundles extending from the IML to the central canal. The transverse dendritic bundles disentangled near the midline and formed a loose dendritic plexus in the region just dorsal to the central canal. PVN-fibers labeled with PHA-L were observed primarily in lamina I and intermediate gray (lamina VII). Although varicose PVN-fibers and SPNs coexisted in the IML, the tight packing of the dendritic bundles prevented any clear demonstration of direct contacts between them. On the other hand, PVN-fibers were occasionally found to appose and wind around the primary or secondary dendrites of some SPNs of the CA and IC. These dendrites were studded with varicosities of PVN-fibers for a short length, and terminal boutons of PVN-fibers were also seen to make contact directly with the dendrites. The results of this study substantiated a direct connection between the PVN and SPNs, using a combination of immunohistochemical techniques for PHA-L and CTb. The possible involvement of a direct pathway from the PVN to SPNs in cardiovascular regulation is discussed.
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  • 91
    ISSN: 1432-1106
    Keywords: Glutamate receptor agonists ; Metabolic inhibitors ; Neurotoxicity ; Hippocampus ; Evoked field potentials ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The perforant path evoked field potentials in the dentate gyrus of the rat hippocampus are distinctive and thus were used as a marker for the accurate positioning of injection cannulae. The time course of the changes in these potentials caused by various toxins were determined and correlated with the extent of neuronal loss produced subsequently. Glutamate and the glutamate receptor agonists, kainate and N-methyl-D-aspartate (NMDA), caused an immediate loss of the evoked field potentials, suggesting a massive depolarization block. After the glutamate agonists there was only a small recovery in potentials over a period of 8 h, whereas after glutamate the potentials recovered within 5 h. Short-term decreases in evoked potential (up to 2 h) were also found after saline injections. Hippocampal evoked potentials were still reduced 8 h after NMDA, even in areas not showing subsequent neuronal loss. Sodium iodoacetate (10 nmol) caused a delayed loss of evoked potentials, reaching a minimum 15 min after injection and lasting for at least 8 h, whereas after sodium cyanide (10 nmol) the potentials decreased immediately to a similar extent to those found 15 min after iodoacetate, but recovery was reversible over 8 h. There was a significant correlation between the degree to which the evoked potentials were decreased and the extent of death of the granule cell neurons, examined histologically four days later.
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  • 92
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    Experimental brain research 86 (1991), S. 182-189 
    ISSN: 1432-1106
    Keywords: Xenograft ; Development ; Trophism ; Retinal ganglion cell ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Fetal rabbit retinae can grow and differentiate when transplanted to the collicular region of neonatal rats. In addition, the observed survival of retinal ganglion cells within grafts is associated with the extension of axons into the superior colliculus of the host brain, suggesting that the factors influencing the guidance of axons and the survival of ganglion cells may be homologous across different mammalian orders.
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  • 93
    ISSN: 1432-1106
    Keywords: Sympathetic preganglionic neurons ; Monoaminergic terminals ; Dendritic organization ; Cholera toxin ; Immunohistochemistry ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary A ladder-like pattern of distribution of sympathetic preganglionic neurons (SPNs) was compared with that of monoaminergic terminals in the upper thoracic spinal cord of the rat. SPNs were identified by a retrograde labeling with cholera toxin subunit B (CTb) injected into the superior cervical ganglia of both sides. Monoaminergic terminals were stained immunohistochemically by using antisera raised against 5-hydroxy-tryptamine (5-HT) or dopamine- β -hydroxylase (DBH). SPNs showing full dendritic arbors were found in all of the sympathetic preganglionic nuclei. They formed a ladder in the horizontal plane. The nucleus intermediolateralis was connected with the central autonomic nucleus by many transverse dendritic bundles. Photomontages of serial sections of material stained alternatively with antisera against CTb and 5-HT or DBH clearly showed a close correlation between SPNs and monoaminergic terminals. There is no transverse dendritic bundle of SPNs without the accompaniment of monoaminergic terminals.
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  • 94
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    Experimental brain research 84 (1991), S. 620-630 
    ISSN: 1432-1106
    Keywords: Substantia nigra ; Serotonin ; Autoreceptor ; Dopamine release ; Nigrostriatal ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Extracellular single unit recordings were obtained from antidromically identified nigrostriatal dopaminergic neurons in anesthetized rats to determine the effects of dorsal raphé stimulation on the somatodendritic excitability of substantia nigra dopaminergic neurons. Stimulation of the dorsal raphé with a brief train of pulses delivered 7–2 ms prior to the neostriatal-evoked antidromic response significantly reduced the proportion of neostriatal-evoked antidromic responses that consisted of both initial segment and somatodendritic components without significantly altering the neostriatal-evoked post-stimulus inhibitory period. Raphé stimulation alone facilitated post-stimulus neuronal firing in almost half of the cells examined. The raphé-induced decrease in somatodendritic excitability was blocked by the serotonin antagonist, metergoline (0.5–2.0 mg/kg, i.v.), without significantly affecting the rate or pattern of spontaneous activity. The tryptophan hydroxylase inhibitor, parachlorophenylalanine (400 mg/kg, i.p. for three consecutive days), abolished the decrease in somatodendritic excitability following raphé stimulation which could be re-instated by intravenous administration of 5-HTP. The dopamine antagonists haloperidol (25–100 μg/kg, i.v.) and sulpiride (10–30 mg/kg, i.v.) also blocked the effects of dorsal raphé stimulation on somatodendritic invasion. These data suggest that in vivo, serotonin liberated from raphé-nigral terminals facilitates the release of dopamine from nigrostriatal dendrites resulting in a local, autoreceptor-mediated reduction in somatodendritic excitability without affecting the spontaneous firing rate and excitability of the neuron as a whole.
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  • 95
    ISSN: 1432-1106
    Keywords: Thyrotropin-releasing hormone (TRH) ; Receptors ; Autoradiography ; Spinal cord ; Experimental transection ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The autoradiographic localization of thyrotropin-releasing hormone (TRH) receptors was investigated in the rat spinal cord after transection at the level of T8–T9. The discrete distribution of [3H]-MeTRH binding was measured with a computerized image analyzer at the cervical (C6–C7) and lumbar (L2–L3) level, one week and three weeks after injury. The TRH receptor density was expressed in fmol/mg protein. There was no significant change in the density of TRH receptors below the injury site. In the cervical region, TRH receptor concentration in the dorsal gray matter did not differ from normal controls; in contrast we found a time-dependent change in lamina 10 and in the ventral gray, with a significant decrease (25% and 19%, respectively) of TRH receptor binding sites one week after transection and a return to control levels by three weeks. From these data and the known increase of TRH immunoreactivity above a spinal injury, a down-regulation of spinal cord TRH receptors in response to elevated levels of TRH is suggested.
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  • 96
    ISSN: 1432-1106
    Keywords: Cranial motor reflex ; Masseter ; Morphology ; Physiology ; Trigeminal ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Motoneurons and muscle spindle afferents of the rat masseter muscle were physiologically and morphologically characterized. Their soma-dendritic morphology and axonal course were investigated using the intracellular horseradish peroxidase method. Following electrical stimulation of the masseter nerve, individual motoneurons were identified by antidromic all-or-none action potentials and individual sensory neurons by orthodromic action potentials. Using threshold separation an excitatory input from muscle spindles to a masseter motoneuron was demonstrated. The short latency difference of 0.34 ms between the mean orthodromic response in the sensory neurons and the beginning of the synaptic potential in the masseter motoneuron suggests a monosynaptic connection between the spindle afferents and the motoneurons. Following intrasomatic horse-radish peroxidase injection large multipolar cell bodies of masseter motoneurons were found within the motor nucleus. Their positions corresponded to the topographic organization of the motor trigeminal nucleus as described in retrograde tracing studies. Dendrites of masseter motoneurons were complex and could be found far beyond the nuclear borders. Distal dendrites extended to the mesencephalic trigeminal nucleus, the supratrigeminal nucleus, the lateral lemniscus and the reticular formation. Within the reticular formation dendrites were seen in the intertrigeminal nucleus and the peritrigeminal zone. Unipolar cell bodies of muscle spindle afferents were found in the mesencephalic trigeminal nucleus after intra-axonal injection of horseradish peroxidase. For all reconstructed sensory neurons a similar axonal course was found. Axonal terminals were found ipsilateral in the motor trigeminal nucleus, indicating a direct connection between sensory neurons and motoneurons. Further collaterals were found ipsilateral in the supratrigeminal nucleus and caudal to the motor trigeminal nucleus in the parvocellular reticular nucleus alpha. Since the latter termination areas are important for bilateral control of jaw-movements, the muscle spindle afferents are likely to participate not only in a monosynaptic motor reflex, but also in more complex neuronal circuits involved in jaw-movements.
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  • 97
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    Experimental brain research 83 (1991), S. 411-418 
    ISSN: 1432-1106
    Keywords: In situ hybridization ; Messenger RNA ; Preprotachykinin A ; Substance P/neurokinin A ; Calcitonin gene-related peptide ; Somatostatin ; Neuropeptide Y ; Cholecystokinin ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary In situ hybridization was used to determine whether genes for neuropeptides [substance P/neurokinin A (SP/NKA), calcitonin gene-related peptide (CGRP), somatostatin (SOM), neuropeptide tyrosine (NPY) and cholecystokinin (CCK)] are expressed in inferior ganglia of the vagus (nodose) and glossopharyngeal (petrosal) nerves. Synthetic oligodeoxyribonucleotides, complementary to the cognate, mRNAs were labeled with [32P] or [35S], and hybridized to 10 μm thick sections of unperfused tissue which were then processed for film and emulsion autoradiography. We found numerous, clustered neuronal perikarya throughout the nodose and petrosal ganglia that expressed preprotachykinin A (SP/NKA) and CGRP mRNAs to varying degrees. Neurons expressing preproSOM mRNA were less abundant and more scattered throughout both ganglia. Notably, we found mRNA for NPY in cells (usually 5–10 per section) in both ganglia. To our knowledge, this is first evidence for NPY in these sensory ganglia. In contrast to previous immunohistochemical findings, we found no evidence for expression of preproCCK in either the nodose or petrosal ganglia. The present findings demonstrate that cells of the nodose and petrosal ganglia express the genes for a number of neuropeptides that are presumably involved with transmission of visceral sensory afferent information to higher order neurons of the central nervous system.
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  • 98
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    Experimental brain research 83 (1991), S. 434-438 
    ISSN: 1432-1106
    Keywords: Nilvadipine ; Ca2+ entry blocker ; Focal cerebral ischemia ; Cerebral edema ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The effects of nilvadipine, a Ca2+ entry blocker, on focal cerebral ischemia were investigated in rats having unilateral middle cerebral artery occlusion. All rats had 24 h ischemia, and were divided into threegroups (ten rats per group). Groups 1 and 2 received 1.0 and 3.2 mg/kg nilvadipine s.c. respectively, just after the occlusion. Control rats received an equal volume of the vehicle. Control animals had a % infarct volume of 28.2 ± 11.4%,and a left/right hemispheric volume ratio of 112 ± 12 %. Group-1 and -2 rats had % infarct volumes of 25.5 ±11.6% and 13.9 ±9.2% (p〈0.01) respectively, and left/right hemispheric volumeratios of 111 ± 9% and 103 ± 7% (p 〈 0.05), respectively. Thus, the drug reduced the infarct size and the brain edema in a dose-dependent manner. The significant decrease in the infarct volumewas observed in the periphery of the frontoparietal cortex. This study supports the hypothesis that nilvadipine may be a potential therapeutic agent for cerebral ischemia. Neuropathological findings suggest the possible therapeutic effects of the drug in the ischemic penumbra.
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  • 99
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    Experimental brain research 83 (1991), S. 683-686 
    ISSN: 1432-1106
    Keywords: Experimental epilepsy ; Penicillin ; Interneurons ; Afterpotentials ; Paroxysmal depolarization shifts ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Interneurons of rat motor cortex in vivo and of rat hippocampal slices were studied during penicillin induced epileptic discharges. Synchronous with pyramidal cells, they showed transient depolarizations similar to paroxysmal depolarization shifts in pyramidal cells. The transient depolarizations were followed by hyperpolarizing or depolarizing afterpotentials lasting 600 to 1200 ms. During the transient depolarizations and the afterdepolarizations the interneurons discharged with increased frequency. This may contribute to the enlarged and prolonged synaptic inhibitions following interictal discharges in pyramidal cells.
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    Experimental brain research 83 (1991), S. 687-690 
    ISSN: 1432-1106
    Keywords: Tetrodotoxin ; Intracerebral injection of drugs ; Edinger ; Westphal nucleus ; Functional ablation ; Pupil ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Spatial extent and duration of the functional blockade elicited by intracerebral injection of tetrodotoxin (TTX) was examined in rats anesthetized with pentobarbital. Pupillary diameter was measured under dissecting microscope before and up to 24 h after injection of TTX (10 ng/l μl saline) into or 1.0, 1.5 and 2.0 mm lateral from the Edinger-Westphal nucleus. TTX administration elicited mydriasis the latency of which was directly and amplitude indirectly proportional to the target-injection distance. The maximum mydriasis attained 3.4 mm, lasted 2 h and slowly decayed over subsequent 20 h. Impulse transmission and conduction was blocked in a spherical volume of tissue about 3 mm in diameter the development of which could be approximated by diffusion from an instantaneous point source. Completeness and full reversibility make the TTX block a convenient research tool.
    Type of Medium: Electronic Resource
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