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  • Electronic Resource  (2,510)
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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Cellular and molecular life sciences 46 (1990), S. 457-458 
    ISSN: 1420-9071
    Keywords: Rat ; carnitine ; lipolysis ; exercise ; glycogen ; triglycerides ; muscle
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary To test the effect of L-carnitine on glycogen sparing when fat oxidation is increased, 100 mg/kg/d were given to rats orally for 3 days, resulting in 1.8-fold higher muscle carnitine levels. Even when FFA were raised by heparin-stimulated lipolysis, the rate of glycogen degradation was not reduced during exercise.
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  • 2
    ISSN: 1432-1440
    Keywords: Vitamin B combination ; Vitamin B6 ; Combined administration: Morphine/Paracetamol ; Antinociception ; Evoked nociceptive activity ; Analgesia ; Thalamus ; Rat ; Acute experiment
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Nociceptive activity was elicited in neurones of the thalamus by supramaximal electrical stimulation of afferent C fibres in the sural nerve of rats under urethane anesthesia. The fixed combination of vitamin B1, B6, B12 (Neurobion®) as well as of vitamin B6 administered by i.p. injection dose-dependently reduced the evoked nociceptive activity. The ED50 of Neurobion® is 4.6 ml/kg (at 100 min after injection) and that of vitamin B6 is 189mg/kg (at 90 min after injection). The minimum effective doses of Neurobion® and vitamin B6 are 0.5 ml/kg and 40 mg/kg, respectively. When Neurobion® or vitamin B6 were given at their minimum effective doses, and the minimum effective doses of morphine (0.025 mg/kg) or paracetamol (5 mg/kg) were injected i.v. 80 min later, i.e., when the maximum effect of higher doses of Neurobion® or vitamin B6was about to develop, no supraadditive effect developed. It is concluded that the antinociceptive effect caused by a single injection of Neurobion® is largely due to vitamin B6. Vitamin B12 may contribute to this effect, whereas vitamin B1 alone exhibited only a slight effect on nociception. Moreover, it appears that Neurobion® produces its antinociceptive effect after a single injection and after repeated administration during several days by different mechanisms so that the effect of analgesic agents is not enhanced following a single injection of Neurobion® but may be enhanced after repeated administration of the compound.
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  • 3
    ISSN: 1432-1440
    Keywords: Vitamin B ; Rat ; EEG ; CNS ; Plasticity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Recording of field potentials from different brain areas of freely behaving rats and subsequent spectral analysis of the signals has proved to be a most sensitive method in pharmacology. This new model is used to measure the effect on the electrical activity of the brain of repeated daily injections of 1 ml/kg of a vitamin B mixture (Neurobion®, 1 ml containing 33.3 mg B1, 33.3 mg B6, and 0.333 mg B12). Subacute application of the vitamin B combination for 1 week in a group of six rats resulted in changes in the power spectra, which became more prominent from day to day. Particularly increases in the power of the alpha1 and beta range from the thalamus dominated the vitamin-induced changes. From the comparison with earlier results obtained with centrally acting serotonergic drugs, it is concluded that the pharmacodynamic action of the vitamin B mixture predominantly influences this transmitter system. The same group of animals, once challenged with a single dose of 0.2 mg/kg morphine before the repeated vitamin treatment, responded to the same challenge after the treatment in a more sensitive manner. Particularly power changes in the beta range were more pronounced. This higher sensitivity to a morphine challenge persisted for more than 1 week after the end of the vitamin treatment which points to a plastic change in serotonergic neurotransmitter control processes. The results obtained here may be linked to the antinociceptive properties of the vitamin B mixture and practical consequences may include a reduction of morphine dose for analgesia during repeated vitamin B treatment.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Naunyn-Schmiedeberg's archives of pharmacology 341 (1990), S. 510-516 
    ISSN: 1432-1912
    Keywords: Myenteric plexus ; Rat ; [3H]Acetylcholine release ; Muscarinic autoinhibition ; Reverse phase HPLC
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Myenteric plexus-longitudinal muscle strips isolated from the small intestine of rats were incubated with [3H]choline to measure the synthesis and the release of [3H]acetylcholine. To separate different radioactive compounds (acetylcholine, choline, phosphorylcholine) from both the tissue and the overflow a new method, the reverse phase HPLC, was used. The radiochromatogram following the injection of a [3H]choline-standard and a [14C]acetylcholine-standard onto the HPLC showed a clear separation of both isotopes with a recovery rate of roughly 100%. Incubation of the muscle strips with [3H]choline caused the synthesis of [3H]acetylcholine (30,000 dpm/preparation) that increased 2-fold, when the electrical field stimulation during labelling was increased from 0.2 Hz to 1 Hz. Electrical field stimulation (3 Hz, 2 min) caused an increase in tritium efflux that was abolished by the removal of extracellular calcium or by the addition of tetrodotoxin. Analysis by reverse phase HPLC of the overflow showed that the stimulated increase in tritium overflow was balanced by the enhanced release of [3H]acetylcholine, whereas the overflow of [3H]choline was not affected by the electrical field stimulation. Oxotremorine (1 μmol/l) suppressed the release of [3H]acetylcholine by 60%. Scopolamine (0.1 μmol/l) prevented this inhibition and, given alone, enhanced the release of [3H]acetylcholine by 43%. The release of [3H]acetylcholine evoked at 0.2, 2 or 20 Hz did not consistently decline at increasing frequencies. The present experiments show the synthesis and the calcium-dependent release of [3H]acetylcholine from the myenteric plexus-longitudinal muscle preparation of rats correspondingly to the same in-vitro preparation isolated from guinea-pigs. Muscarinic autoinhibition operates also in the small intestine of rats. However, some differences (frequency-dependency of [3H]acetylcholine release, spontaneous neuronal activity) are evident between both species. Reverse phase HPLC is a useful method to separate radioactive choline and acetylcholine with a high recovery rate.
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Naunyn-Schmiedeberg's archives of pharmacology 342 (1990), S. 719-721 
    ISSN: 1432-1912
    Keywords: Autoradiography ; Dopamine DA-1 receptors ; Kidney ; Juxtaglomerular cells ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The binding of the selective DA-1 receptor antagonist [3H]-SCH 23390 in sections of rat kidney was studied using combined in vitro biochemical radio-receptor assay and autoradiography. [3H]-SCH 23390 was bound to sections of rat kidney in a manner consistent with the labeling of DA-1 receptors with a disssociation constant value of 4.2 nmol/l and a Bmax value of 180.6 fmol/mg protein. Light microscope autoradiography revealed a dense accumulation of silver grains in juxtaglomerular cells and in proximal convoluted tubule cells. These findings suggest that the stimulation of renin release elicited by dopamine and DA-1 receptor agonists may be mediated by the activation of DA-1 receptors located on juxtaglomerular cells.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Journal of molecular medicine 68 (1990), S. 125-128 
    ISSN: 1432-1440
    Keywords: B-vitamins ; Spinal dorsal horn ; Afferent inhibition ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Afferent inhibition of spinal dorsal horn neuronal responses to noxious skin heating was induced by transcutaneous electrical nerve stimulation in pentobarbital-anesthetized rats. Pretreatment with B vitamins significantly enhanced this afferent inhibition, possibly due to an increase in the synthesis rate of inhibitory neurotransmitters in central neurones.
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  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Journal of molecular medicine 68 (1990), S. 142-145 
    ISSN: 1432-1440
    Keywords: Pyridoxine ; B Vitamins ; CNS ; Serotonin receptor binding ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Treatment of normal adult rats with pyridoxine or a B-vitamin mixture resembling Neurobion® 1 led to an increase in serotonin content of various brain areas and to a decrease in the number of serotonin S2 receptors. The results indicate that the pyridoxal phosphate level in regions of the brain regulates the extent of decarboxylation of 5-hydroxytryptophan, the precursor of serotonin. The results also suggest a continuum from deficiency in pyridoxine to treatment of animals with a moderate excess of pyridoxine which is reflected in the synthesis and secretion into the synaptic cleft of the neurotransmitter serotonin.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Springer
    Biology and fertility of soils 9 (1990), S. 101-109 
    ISSN: 1432-0789
    Keywords: Phryganella acropodia ; Testate amoeba ; Growth rate ; Rhizopoda ; Feeding ; Fungal species ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Clones of Phryganella acropodia were cultivated under different trophic conditions with bacteria as the food source. The doubling time was estimated to be 3 days. The edibility of four species of fungi, Aspergillus niger, Cunninghamella echinulata, Penicillium echinulatum and Stilbella bulbicola, was tested, but only Penicillium enchinulatum and Stilbella bulbicola were eaten and digested by the amoeba. An ultrastructure examination showed that there are two contractile vacuoles, many dictyosomes, a single nucleus with several nucleoli, and peroxisomes. The pseudopodia are filiform when attached to the substrate but change to lobose when the animal is floating. A thin organic membrane covers the aperture of resting forms.
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  • 9
    ISSN: 1432-2307
    Keywords: Gastric carcinoma ; Capillaries ; von Willebrand factor ; Ultrastructure ; Immuno-electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The microvasculature of the stroma of human gastric carcinoma was studied by immuno-electron microscopy for factor VIII/von Willebrand factor (vWF) and conventional electron microscopy. In differentiated type (intestinal) gastric carcinoma (9 cases), capillaries were distributed more densely around carcinoma cell nests. vWF was localized in endothelial cells and neighbouring stroma. Ultrastructurally, capillary endothelial cells showed considerable hypertrophic changes with well-developed rough endoplasmic reticulum (rER). vWF was localized in well-developed rER, granules, Weibel-Palade bodies (WPB), in the vascular lumen as clusters, and diffusely deposited in the subendothelium. This indicates that endothelial cells in this group are transformed into a state of active protein production. In undifferentiated type (diffuse) gastric carcinoma (12 cases), capillaries were uniformly distributed and endothelial hypertrophic changes were less remarkable. vWF was localized in WPB, scanty rER and subendothelial matrix. Solid capillary buds were observed in both types; they were composed of a solid strand of endothelial cells without a visible lumen. Our results reveal that the microvasculature in tumour stroma differs significantly according to its histological type.
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  • 10
    ISSN: 1432-2307
    Keywords: Mucus-granule-containing ciliated cell ; Ciliated metaplasia ; Transitional form ; Gastric mucosa ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Ciliated cells were found in the gastric mucosa in close association with intestinal metaplasia, mainly in the pyloric mucosa, of Japanese patients. The occurrence of ciliated cells is believed to be an acquired phenomenon and is considered to be a type of metaplasia; the term “ciliated metaplasia” is used to describe this phenomenon. Ciliated cells are found in the basal part of the glands among normal-looking mucous cells, mucous neck cells and neuroendocrine cells, but never on the surface or in foveolar epithelium. In ciliated cellcontaining glands, mitoses were noted in the neck region and the ultrastructural features of these cells were identical to those of undifferentiated neck cells. However, cell metaplasia from undifferentiated cells to metaplastic ciliated cells has never been demonstrated previously. The small mucus-granule-containing ciliated cells found in our present study may arise subsequent to division of undifferentiated neck cells into mucous cells with some daughter cells then exhibiting differentiation characteristics specific to ciliated cells. Thus they contain a mixture of both small mucus granules and numerous basal bodies and cilia, at the same time as a transitional form.
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  • 11
    ISSN: 1432-2307
    Keywords: Cardiomyopathies ; Ultrastructure ; Morphometry ; Mitochondria ; Myofibrils
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary We performed an ultrastructural, morphometric comparison of mitochondria and myofibrils of cardiomyocytes using endomyocardial biopsy specimens in hypertrophic cardiomyopathy (HCM) and dilated cardiomyopathy (DCM). Biopsies came from the right ventricular side of the interventricular septum in nine patients with HCM, nine with DCM, and nine controls with arrhythmia and/or ST depression. Morphometric analysis was carried out using electron microscopic photographs and an image analyser. Mitochondria were significantly greater in number and smaller in size in HCM than in the control group. In DCM, the size of mitochondria was also significantly smaller than in the control group, although their number was similar to that of the control group. No statistically significant difference was found regarding the size of mitochondria between HCM and DCM. The percentages of both mitochondrial and myofibrillar areas in cytoplasm were smaller in the DCM than the HCM and control groups, though no difference was seen between the latter two. The ratio of mitochondrial area to myofibrillar area was almost the same in each group. These results suggest increased mitochondrial function to match hypertrophic cardiomyocytes in HCM, and decreased mitochondrial function and cardiomyocytic contractility in DCM.
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  • 12
    Electronic Resource
    Electronic Resource
    Springer
    Virchows Archiv 417 (1990), S. 113-118 
    ISSN: 1432-2307
    Keywords: Minute chemodectoma ; Lung ; Ultrastructure ; Immunohistochemistry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary So-called minute pulmonary chemodectoma is a curious, small lung tumour found mainly in women. The nature and origin of the proliferating cells are still obscure. In the first report on the tumour, the component cells were described as resembling chemoreceptor cells and the tumour was named chemodectoma. However, electron microscopic studies of the tumour have revealed no evidence of neuronal characteristics and have shown a close resemblance to meningothelial cells. In this study, the electron microscopic findings were similar to those previously reported but in one of the two cases, tumour cells were filled with abundant cytofilaments, giving them an occasional dense, patch-like appearance. Immunostaining for myosin and vimentin was positive in all tumour cells, but epithelial membrane antigen staining was not seen. These findings indicate that the tumour might have its origin from muscle cells.
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  • 13
    Electronic Resource
    Electronic Resource
    Springer
    Virchows Archiv 417 (1990), S. 395-404 
    ISSN: 1432-2307
    Keywords: Ultrastructure ; Non-Hodgkin's lymphoma ; Signet-ring cell ; Endoplasmic reticulum ; Multivesicular body
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary New ultrastructural findings are reported from two lymphomas of vacuolar signet-ring cell morphology (SR+), one of B cell and one of T cell lineage. When these lymphomas were compared ultrastructurally a difference in the relationship of the endoplasmic reticulum (ER) to the vacuole was noted, although the fine structure of the vacuoles themselves was similar and they were interpreted as giant multivesicular bodies (mvbs). Smooth ER was found near the vacuoles in both cases. Dark mvbs with a complex, reticulate form are emphasised as readily identified but hitherto unreported cell components in these tumours. A further B cell lymphoma of centroblastic/centrocytic type which was SR− was found to be rich in mvbs and may be a transitional form between SR− and SR+ lymphomas. In addition, the occurrence of mvbs has been studied quantitatively in a number of other lymphomas and in B and T lymphocytes in reactive nodes. Although increased numbers of mvbs were found in neoplastic compared with reactive lymphocytes, and in T compared with B cell lymphomas, these differences were not statistically significant. The possible roles of endoplasmic reticulum and mvbs in the generation of SR+ change are discussed.
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  • 14
    ISSN: 1432-2307
    Keywords: Purkinje fibres ; Transitional cells ; Working myocardium ; Global ischaemia ; Ultrastructure ; Contraction state
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Contraction bands usually occur in the intramural working myocardium following post-ischaemic reperfusion. In the subendocardium, however, they are found during ischaemia. Thus, we ascertained the contraction states of Purkinje fibres, transitional cells, subendocardial and intramural parts of the working myocardium during 30 min global ischaemia at 25° C. The effects with and without myocardial protection were compared. At the onset of pure ischaemia contraction bands are completely lacking in all cell types. During pure ischaemia contraction bands are found in all subendocardial cell types but not in the intramural working myocardium. A peak of pathological contraction states is found in the intramural working myocardium at the onset (0 min), in the subendocardial working myocardium at 10 min, in the transitional cells and Purkinje fibres at 30 min of pure ischaemia. Histidine-, tryptophan-, ketoglutarate-enriched (HTK) cardioplegia prevents contraction bands completely at the onset of ischaemia and prevents both contraction bands and pathological contraction states during ischaemia almost completely. Striking differences in the physiological contraction states are seen only in the working myocardium: HTK cardioplegia brings about dominance of relaxation during ischaemia. These findings may be due mainly to the effects of global ischaemia on the one hand and to catecholamines, calcium and oxygen on the other.
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  • 15
    Electronic Resource
    Electronic Resource
    Springer
    Virchows Archiv 417 (1990), S. 443-447 
    ISSN: 1432-2307
    Keywords: Mesothelioma ; Pathology ; Ultrastructure ; Peritoneum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Well-differentiated papillary mesothelioma (WDPM) is considered to be a distinct subtype of peritoneal mesothelioma. Although the WDPM is usually qualified as benign, the natural history of this lesion has not been clearly established. This report relates to two WDPMs which were found incidentally. In a 51-year-old man the WDPM developed over a period of 5 years into a typically malignant diffuse mesothelioma. Thus, although the WDPM morphologically lacks signs of malignancy, it should be regarded as a borderline mesothelioma.
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  • 16
    ISSN: 1434-0879
    Keywords: Rat ; Urinary bladder ; Partial cystectomy ; Stimulation of urothelial proliferation ; N-butyl-N-(4-hydroxybutyl)-nitrosamine ; Tumor development
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Tumor development was investigated in the partially resected, proliferating urinary bladder or rats in dependence upon the onset of stimulated de novo DNA synthesis related to carcinogen dosing. N-butyl-N-(4-hydroxybutyl)-nitrosamine (BBN) was used as carcinogen and administered by gavage in three fractionated doses (100 mg/kg body weight each) either during the phase of the most pronouced proliferation of the urothelium 30, 45 and 70 h after one-third resection of the bladder or 24 h and 1 week prior to partial cystectomy. When BBN was given during most increased DNA synthesis subsequent to one-third resection, the incidence of bladder tumors was reduced to 8.7% compared with 19.6% found in control animals with a non-resected, quiescent bladder. Tumor formation was neither inhibited nor enhanced when BBN was initially administered, followed by partial cystectomy 24 h or 1 week after the last carcinogen dose, yielding tumor incidences of 18.2% and 22.5%, respectively. Thus, the feeding of BBN during the period of maximum DNA synthesis inhibited tumor development in the partially resected bladder, while stimulation of cell replication subsequent to carcinogen administration did not influence the carcinogenic process initiated. The results obtained indicate that time of onset of stimulated DNA synthesis related to carcinogen dosing is the decisive factor in modifying urothelial carcinogenesis in the proliferating urinary bladder.
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  • 17
    Electronic Resource
    Electronic Resource
    Springer
    Urological research 18 (1990), S. 345-348 
    ISSN: 1434-0879
    Keywords: Urinary bladder ; Overdistension ; Adrenergic innervation ; SIF cells ; Glyoxylic acid ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The effect of distension on adrenergic innervation was investigated in the rat urinary bladder. Bladders were distended for 3 h by forced diuresis and ballon obstruction, and specimens were taken from the bladder dome, body and neck for the demonstration of glyoxylic acid-induced fluorescence of catecholamines. Depletion of catecholamines started after 10 h and was almost complete after 2 days. The fluorescence had recovered part way after 5–7 days and was practically normal after 21 days. Small, intensely fluorescent (SIF) cells in the ganglia continued to leak catecholamines throughout the 21-day study period. The primary clinical success of distension therapy for the treatment of unstable bladder may be at least partly due to a reversible disturbance in the function of the adrenergic nerves, which have an excitatory alpha-adrenergic dominance in such cases, but the persistent leakage from SIF cells raises the question of whether distension causes prolonged disturbances in bladder function.
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  • 18
    ISSN: 1432-0533
    Keywords: Olivopontocerbellar atrophy ; Argyrophilic inclusion ; Pontine nucleus ; Ubiquitin ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Patients with olivopontocerebellar atrophy (OPCA) were studied, and cytoplasmic inclusions were observed in some of the remaining neurons of the pontine nuclei, nuclei reticularis tegmenti pontis and arcuate nuclei. The cytoplasmic argyrophilic inclusions were demonstrated by silver impregnation techniques such as Bielschowsky and Bodian staining. With hematoxylin and eosin stain, the inclusions were sharply demarcated and appeared pale. The inclusions were not stained by the following routine histological methods: Klüver-Barrera, phosphotungstic acid hematoxylin, Holzer, periodic acid-Schiff, Mallory azan, alcian blue, nile blue, Masson trichrome, Congo red, thioflavine S, oil red O and Sudan black B stains. Immunohistochemistry with anti-ubiquitin antiserum showed that these inclusions were ubiquitinated. However, the inclusions did not react with any of the following antibodies (Abs) or antisera: anti-phosphorylated neurofilament (NF) Ab, anti-nonphosphorylated NF Abs (160 and 200 kDa), anti-paired helical filament antiserum, anti-tau antiserum, anti-tubulin Abs (alpha and beta), anti-microtubule-associated proteins antiserum, anti-glial fibrillary acidic protein antiserum, anti-vimentin Ab, anti-desmin Ab, anti-cytokeratin Abs (low and high molecular weights), anti-actin antiserum, anti-skeletal myosin antiserum and anti-myelin basic protein Ab. Ultrastructurally, the inclusion bodies noted in OPCA were composed primarily of fibrils having a width ranging from about 24 to 40 nm, which were entirely coated with osmiophilic granular material along their whole length. They were occasionally intermingled with a few filaments about 10 nm in width. Electron microscopical examination on silver-impregnated specimens revealed that each granule-coated fibril had a great affinity for silver particles. In elucidating the pathogenesis of OPCA, it was considered to be an important neuropathological finding that some of the remaining pontine neurons affected by OPCA developed characteristic cytoplasmic argyrophilic inclusions.
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  • 19
    ISSN: 1432-0533
    Keywords: Rat ; Mongolian gerbil ; Trimethyltin ; Dense bodies ; Golgi appratus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The different responses of neurons with distinctive variations in morphology and function, confirm earlier observations of the lack of uniformity in the reaction of nerve cells to trimethyltin. Thus, hippocampal pyramidal and cortical neurons in both rat and Mongolian gerbil (M. unguiculatus) show abundant lysosomal dense bodies and disorganisation of the protein-synthesising apparatus. Cerebellar Purkinje cells in gerbil, but not in rat, show striking increases in smooth membrane systems, while dense bodies are insignificant in both species; large motor-type neurons in brain stem and spinal cord in both species do not accumulate dense bodies, but their rough endoplasmic reticulum (RER) may undergo intense vacuolation with or without subsequent cell death; and by contrast, spinal ganglion cells of both species may form an excess of dense bodies and, in the gerbil, vacuolation of RER. In contrast with these varied responses to trimethyltin most neurons, large and small, in both species regularly undergo striking vacuolation of the Golgi apparatus in the earliest phase of the intoxication, a constant feature that probably reflects the site of the primary cytotoxic lesion; all other changes we consider are secondary to such damage to the Golgi apparatus, however this may come about. These observations are discussed in relation to earlier reports of the variable effects of trimethyltin and with the metabolic changes reported in trimethyltin intoxication that in general accord with these morphological conclusions.
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  • 20
    ISSN: 1432-0568
    Keywords: Creatine kinase ; Development ; Distribution ; Rat ; Heart ; Muscle ; Immunohistochemistry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The distribution pattern of creatine kinase (E.C 2.7.3.2) isozymes in prenatal rat heart and skeletal muscle was studied by immunohistochemistry. Between embryonic day (ED) 12–18, creatine kinase M (CK-M) is heterogeneously expressed in the heart: a pronounced staining of CK-M is first observed in the outflow tract and the trabeculae of the right ventricle (ED12-14), and subsequently in the venous valves, the interatrial septum and the sinoatrial node. From ED18 onwards, a homogeneous expression of CK-M is observed due to an increase in isozyme concentration in the remaining part of the myocardium. By contrast, the developmental appearance of creatine kinase B (CK-B) occurs almost homogeneously throughout the heart between ED11-14. Thereafter, a decrease of the CK-B is first observed in the inflow tract (in particular in the sinoatrial node), in the inner part of those atrial walls that are adjacent to the atrioventricular junction, and temporarily in a band in the upper part of the interventricular septum. From ED18, a selective disappearance of CK-B is found in the papillary muscle of the left ventricle. At birth, a considerable amount of CK-B remains present in the ventricular walls. Although some of the stage-dependent regional differences in expression of the creatine kinase isozymes, in particular those of the M-subunit, are shared by other mammalian and avian species, their significance for the developmental changes in the physiology of the heart is speculative at present.
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  • 21
    ISSN: 1432-0568
    Keywords: Chloride cell ; Teleost ; Gills ; Ultrastructure ; Adaptation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The general gill morphology of Oreochromis alcalicus grahami, a teleost adapted to high salinity and hyperosmosis, is basically similar to that of other teleostean fish. The species has four pairs of gill arches, all of which have well developed filaments. Each of the arches (holobranchs) has two rows of filaments (hemibranchs). Bilaterally situated secondary lamellae branch from the central axis of the filaments. The lamellae reach their maximum size at the middle of the filament, gradually decrease in size and eventually disappear towards the tip of the filament, which is bare. The leading edge of the gill filament and the immediate interlamellar space is covered by a stratified epithelium consisting of pavement cells, mucous cells, chloride cells and undifferentiated cells. The surface of these cells is made up of concentric microridges. The chloride cells were found only on the primary epithelium (filamental epithelium) and very rarely on the secondary epithelium (lamellar epithelium). Two types of chloride cells were observed in the gills of Oreochromis. The superficial chloride cells have fewer mitochondria concentrated towards the basal aspect of the cell, and a network of tubules towards the apical surface and are less electron dense. These cells intercommunicate with the water through an apical pore. The deep chloride cells have numerous diffuse mitochondria intercalated between a fine profuse tubular network and are more electron dense. These cells are covered by one or more layers of pavement cells and thus do not have access to the external surface. After gradual dilution of the lake water in which the fish were kept, both types of chloride cells remained topographically and ultrastructurally distinct. However, in both kinds of cell the mitochondria decreased in number and size. Initially there was an increase in the diameter and the degree of interdigitation of the tubules followed by a gradual decrease. An increase in the quantity of rough endoplasmic reticulum, particularly at the perinuclear region of the cell, was noted. The morphometric analysis of the branchial system indicated that the gills of Oreochromis are well adapted for gas exchange by having numerous and relatively long gill filaments with a high lamellar density. These features provide a large surface for gas exchange which, when coupled with the notably thin water-blood barrier of an average thickness of only 0.83 μm, would facilitate efficient absorption of oxygen by the gills. Oreochromis alcalicus was observed to be incapable of adapting to freshwater. This may have been due to the progressive degeneration of the chloride cells. Also the arrangement of the chloride cells as a continuum from the central venous compartments to the free epithelial surface is a structural feature which may not be amenable to radical functional changes.
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  • 22
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    Anatomy and embryology 181 (1990), S. 195-213 
    ISSN: 1432-0568
    Keywords: Cell death ; Degeneration ; Embryo ; Development ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Physiological cell death is a widespread phenomenon in the development of both vertebrates and invertebrates. This review concentrates on an aspect of developmental cell death that has tended to be neglected, the manner in which the cells are dismantled. It is emphasized that the dying cells may adopt one of at least three different morphological types: “apoptotic”, “autophagic”, and “non-lysosomal vesiculate”. These probably reflect a corresponding multiplicity of intracellular events. In particular, the destruction of the cytoplasm in these three types appears to be achieved primarily by heterophagy, by autophagy and by non-lysosomal degradation, respectively. The various mechanisms underlying both nuclear and cytoplasmic destruction are reviewed in detail. The multiplicity of destructive mechanisms needs to be born in mind in studies of other aspects of cell death such as the signals which trigger it, since different signals probably trigger different types of cell death.
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  • 23
    ISSN: 1432-0568
    Keywords: Basket cells ; Hippocampus ; Dentate gyrus ; Rat ; Postnatal development
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Light and electron microscopic preparations were used to analyze the postnatal development of the basket cells of the rat dentate gyrus. The basket cells, located at the hilar border, were recognized in 2-day-old rats in Golgi preparations, where they displayed immature dendrites and a small axon arbor in the granule cell layer. At 5 days, the basket cells were found to have a large perikaryal cytoplasm, a round nucleus, an axon that forms symmetric synapses with granule cells, and dendrites and somata that are contacted by other axon terminals. The 10-day basket cells display more mature features, such as Nissl bodies and well-developed Golgi complexes. The basket cells from 16-day-old rats are mature in terms of their ultrastructural features, in that the nuclei are highly indented and display intranuclear rods or sheets, the perikaryal cytoplasm is packed with organelles, and the axon has developed an extensive arborization with the somata and dendrites of granule cells at the border with the molecular layer. This arborization will continue to expand as more granule cells are generated and added to the hilar border. These data correlate well with the immunocytochemical and biochemical development of GABAergic neurons in the dentate gyrus. Furthermore, the maturation of the structure of basket cells appears to precede the appearance of adult-like electrical activity in the hippocampus.
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  • 24
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    Acta neuropathologica 80 (1990), S. 118-122 
    ISSN: 1432-0533
    Keywords: Mitochondrial encephalomyopathy ; Extraocular muscle ; Ultrastructure ; Mitochondrial myopathy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary We carried out a histological examination of the extraocular muscles (EOMs) in a case of myoclonus epilepsy associated with ragged-red fibers (MERRF) and two cases of mitochondrial myopathy, encephalopathy, laetic acidosis, and stroke-like episodes (MELAS), which did not manifest external ophthalmoplegia clinically. By light microscopy, many granular and vesicular fibers were seen associated with endomysial fibrosis. Electron microscopy revealed that the fibers showed prominent accumulation of abnormal mitochondria, extensive loss of myofibrils, proliferation of free sarcoplasmic reticulum and an increased amount of lipid vacuoles. These changes were more pronounced in MELAS than in MERRF. Hirano bodies were often seen in the subsarcolemmal area of muscle fibers and also in the intramuscular myelinated nerve fibers and axon terminals. These findings suggest the presence of mitochondrial myopathy of the EOMs in cases of MELAS and MERRF.
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  • 25
    ISSN: 1432-0533
    Keywords: Cerebral ischemia ; Delayed neuronal death ; Gerbil ; Hippocampus ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Ultrastructural damage leading to delayed neuronal death was investigated in the mid-CA1 region of the hippocampus from the stratum (str.) moleculare to oriens after transient bilateral forebrain ischemia in Mongolian gerbils. After ischemia for 5 min without recirculation, mild swelling of the peripheral part of the apical and basal dendrites was already apparent in the str. moleculare and str. oriens. Mitochondria in the dendrites were also swollen in the same area. During recirculation for 12 h to 3 days, swelling of the dendritic cytoplasm persisted with formation of microvacuoles, but swelling of mitochondria receded. Microvacuolation and loss of microtubules were also observed in the proximal part of the dendrites during this period, and swelling and disruption of internal cristae were observed in mitochondria after recirculation for 3 days. The dendrites became severely degenerated after recirculation for 4 days. In the pyramidal cell bodies, no abnormality was observed at the end of ischemia for 5 min, but disaggregation of polyribosomes and swelling of the endoplasmic reticulum were observed 12 h after recirculation. Proliferation of the endoplasmic reticulum in parallel arrays occurred after recirculation for 1 day and persisted. Severe degeneration of the pyramidal cell bodies was obvious after recirculation for 4 days. The findings observed in the present investigation suggested that the neuronal structure most vulnerable to ischemia was the peripheral part of the dendrites and postischemic neuronal damage occurred early in this part of the dendrites.
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  • 26
    ISSN: 1432-0533
    Keywords: Feline ; Olfactory neuroblastoma ; Type C retrovirus ; Immunocytochemistry ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Three cases of spontaneous olfactory neuroblastoma (ONB) in domestic cats were morphologically and immunocytochemically characterized. Diagnostic light microscopic features included Flexner and Homer-Wright rosettes, while ultrastructurally the cells had neuritic processes, intracellular intermediate filaments, and intercellular junctions. Immunocytochemically, the tumors stained positively for neuron-specific enolase, cytokeratins, and S-100 protein antigens. In each case, a key finding was the identification of numerous mature type C retroviral particles within the tumors. In one case, budding of viral particles from the plasmalemma of tumor cells suggested the source of mature particles. This cat and one other were tested, and both were serologically positive for feline leukemia virus (FeLV). The virus in the tumors was identified as FeLV by polymerase chain reaction and immunocytochemistry. No other neoplasms were found in any of the cats, nor was there similar evidence of active viral infection in other non-tumor tissues, including the brain. Although the relationship between FeLV infection and ONB is uncertain, our findings indicate that FeLV should be investigated as an etiologic agent of ONB.
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  • 27
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    Acta neuropathologica 80 (1990), S. 611-617 
    ISSN: 1432-0533
    Keywords: Intranuclear inclusions ; Endoplasmic reticulum ; Hyaline inclusions ; Striated muscle ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Large intracytoplasmic inclusions arising from the endoplasmic reticulum and nuclear envelope were found in the muscle fibers of a 32-year-old individual with a life-long, chronic and progressive sensory-motor neuropathy. The morphological features of the inclusions were similar to that occasionally reported in the striated muscles in several unrelated conditions as well as to “hyaline” or “colloid” inclusions commonly seen in motor neurons of the brain stem and spinal cord. The chemical nature of the inclusions is not known. Their occurrence in the muscle fibers is probably secondary to chronic denervation.
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  • 28
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    Acta neuropathologica 80 (1990), S. 597-603 
    ISSN: 1432-0533
    Keywords: Choroid plexus ; Amyloid ; Intracellular inclusions ; Ultrastructure ; Immunocytochemistry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Intracellular inclusions with staining properties of amyloid are very common in the aging choroid plexus epithelial cells. In many ways these inclusions show similarities with the neurofibrillary tangles, found in cerebral cortical neurons in patients with Alzheimer's dementia. We have now designed a purification method for choroid plexus amyloid and performed a transmission and scanning electron miscroscopic study. This shows that one form of choroid plexus inclusions, the Biondi ring, is a homogeneous globule covered with a thin layer of amyloid fibrils. Partial immunochemical characterization of the choroid plexus amyloid reveals that it is different from the neurofibrillary tangles although there are similarities.
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  • 29
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    Anatomy and embryology 182 (1990), S. 103-112 
    ISSN: 1432-0568
    Keywords: Fibroblast ; Myofibroblast ; Interstitial cell ; Vitamin A storing cell ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Scanning electron microscopic observations of connective tissue cells show a new aspect of the nature of fibroblasts, and the subsequent broad survey of references makes clear that fibroblasts of many tissues have various features which are regarded as atypical of fibroblasts, and at the same time that various connective tissue cells in different organs have features typical of fibroblasts. Both morphological and functional features of fibroblasts are more or less common to those of fibroblast-like cells, and differences among these cells are quantitative rather than qualitative. Therefore, it is almost impossible to set clear-cut criteria for distinguishing genuine fibroblasts from a large population of fibroblast-like cells. The majority of cells sharing features of fibroblasts, if not all, seem to belong to the same population of cells. They are probably adapted to special functional needs in their own micro-environment that are peculiar to local or pathological or experimental conditions. It is proposed to categorize these cells into subtypes depending on their main functions: 1, fibrogenesis; 2, tissue skeleton or barrier; 3, intercellular communication system; 4, gentle contractile machinery; 5, endocrine activity; and 6, vitamin A-storing. Re-evaluation of fibroblasts and fibroblast-like cells is required to facilitate their better understanding.
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  • 30
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    Anatomy and embryology 182 (1990), S. 225-234 
    ISSN: 1432-0568
    Keywords: Cranial veins ; Basal drainage ; Development ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The anatomical pattern and development of the venous system of the cranial base in the rat is described. The anatomy of the venous system was determined from observations of vascular casts in adult ratss; the development of the vascular system was established by examination of ink-injected embryos. A transverse sinus system was found to be present in the basal venous system. The sinus connects the posterior facial veins; its middle section transverses the cranial base through the basisphenoid canal, and it receives the venae ophthalmicae within the basisphenoid bone. The venae ophthalmicae in turn are connected to the perioptic veins and to the sinus interperiopticus intracranially. Dorsally, the venae ophthalmicae anastomose with the paired sinus cavernosus. The term sinus transversus basalis is proposed for the venous connection between the posterior facial veins within the basisphenoid bone of the rat. The anlage of the sinus transversus basalis is established by vascular networks during the final prenatal period, its formation, however, is only completed postnatally. The anlages of the venae periopticae, the venae ophthalmicae, the sinus cavernosus and the rami intercavernosi are already established at early developmental stages. The characteristic pattern is formed before birth.
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  • 31
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    Anatomy and embryology 181 (1990), S. 325-331 
    ISSN: 1432-0568
    Keywords: Oocyte maturation ; Ultrastructure ; Fox ; Ovulation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Blood samples were taken weekly from seventeen mature blue fox vixens (average age five years), from late anoestrus until pro-oestrus, and then taken daily. The vixens were sacrificed at various stages of oestrus, and oocytes were collected from ovarian follicles by aspiration, and/or from oviducts by flushing. The structural features of oocyte maturation were related to the time of the luteinizing hormone (LH) peak. On days 1–2 after the LH peak the oocyte nucleus migrated from a central to a peripheral position in the ooplasm and assumed a flattened appearance. The cumulus investment expanded simultaneously and ovulation took place around day 2. On days 2–3 the oocyte nuclear envelope broke down, the nucleoli disappeared, the metaphase of the first meiotic division was reached, the Golgi complexes decreased in size, the perivitelline space enlarged, and all junctional contact between cumulus cell projections and oocyte was disrupted. On days 3–5 the first polar body was extruded, the metaphase of the second meiotic division was reached, and the cumulus cells degenerated. On day 5 the release of cortical granule content was occasionally seen, and from day 6 the oocytes showed signs of degeneration. In a few animals deviant oocyte maturation was noticed.
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  • 32
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    Anatomy and embryology 181 (1990), S. 37-48 
    ISSN: 1432-0568
    Keywords: Axons ; Astrocytes ; Oligodendrocytes ; Ultrastructure ; Paedomorphosis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary In five species of lungless salamanders, family Plethodontidae, which all show highly developed visual abilities, the ultrastructure of the optic nerve was investigated and the total number of retinal ganglion cell axons, the percentage of myelinated axons, and the volume densities of glia and axons were determined. More than 80% of all axons were smaller than 0.4 μm and only 2–3% were larger than 0.8 μm. In individual nerves the degree of myelination varied between 1 and 9% which is in the range reported for other amphibian species. The miniaturized and highly paedomorphic species Batrachoseps attenuatus was an exception because only very few or even no myelinated axons were present in the nerve, which is unique among gnathostome vertebrates. The five investigated species had total numbers of axons ranging from 26000 in Batrachoseps attenuatus to about 50000 in Plethodon jordani. These numbers are the lowest found among vertebrates with an elaborated visual system. The amount of glial material in the optic nerve varied between 25 and 50%, with larger nerves possessing more glia than smaller ones. Ultrastructural analysis revealed that the optic nerve of each species contained both astrocytes and oligodendrocytes, although often in immature form. In Batrachoseps attenuatus the glia showed features of both astrocytes and oligodendrocytes which reflect an undifferentiated state.
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  • 33
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    Anatomy and embryology 181 (1990), S. 59-66 
    ISSN: 1432-0568
    Keywords: Ultrastructure ; Marmoset ; Chorionic villi
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The ultrastructural morphology of developing chorionic villi in the marmoset monkey (Callithrix jacchus) placenta was studied in pregnant monkeys at known time intervals after ovulation. In samples obtained at 45 days after ovulation the mesoderm, which consists of primitive foetal blood vessels, is seen to extend down into cytotrophoblast columns. Syncytiotrophoblast completely surrounds maternal blood vessels and both basal laminae and endothelial cells of maternal origin show signs of disorganisation and degradation. Syncytiotrophoblast is first observed to breach the maternal circulation in samples collected from animals at 60 days after ovulation; this results in discrete haemochorial villi randomly distributed throughout the placental bed. Samples obtained at 80 days after ovulation and term placental samples (145 days after ovulation) exhibit tertiary haemochorial villi throughout the placenta, similar to those seen randomly distributed at 60 days after ovulation.
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  • 34
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    Anatomy and embryology 181 (1990), S. 75-82 
    ISSN: 1432-0568
    Keywords: Anuran lymph hearts ; Development ; Ultrastructure ; Myogenesis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The early development of anuran posterior lymph hearts studied by light- and electron-microscopy in frog larval stages 25–29 (Gosner 1960) can be subdivided into three phases. In phase I, mesenchymal myogenic cells are found, each possessing a single 9 + 0 cilium and numerous filopode-like processes aggregated near the vena caudalis lateralis, forming up to three metameric organ anlagen arranged like a cuff around the preexisting lymphatics (stages 26/27). In phase II, cell proliferation starts at stage 28 within the lymph heart wall as does the formation of primarily polynuclear myofibres by fusion of several myoblasts. At this stage immature myofibres show a vast sarcoplasm, a poorly developed SR and only few myofibrils with not yet distinguishable A- and I-bands. In phase III, the afferent and efferent valves are formed at the onset of pulsation in stage 29. Contractile myofibres contain large glycogen fields and a considerable amount of myofibrils which frequently branch and show distinct Z-lines, A-, I-, H- and M-bands; 1–3 cilia were found lying within a channel-like cell invagination. The peculiarities of organogenesis and myofibre development are discussed.
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  • 35
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    Anatomy and embryology 181 (1990), S. 603-614 
    ISSN: 1432-0568
    Keywords: Neocortex ; Rat ; 2-deoxyglucose ; Local cerebral glucose utilization ; Laminar pattern ; Image analysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The neocortex of the rat brain can be subdivided into regions of different local cerebral glucose utilization (LCGU). However, only a few neocortical areas can be delineated by differences in mean LCGUs between neighbouring areas. These area borders correspond exactly with cytoarchitectonically defined borders found in adjacent Nissl-stained preparations. On the other hand, nearly all of the architectonically defined area borders are also recognizable in the LCGU pictures, if differences in laminar distribution patterns of LCGU are taken into account. Furthermore, interareal differences in mean LCGU mainly reflect changes in layer IV, whereas layers II–III and V–VI show nearly identical LCGU values in all neocortical areas of the rat brain. The primary sensory areas exhibit the highest LCGU in layer IV, while the primary motor cortex shows a high LCGU in layer V. As the cytoarchitectonically defined pattern of the cortex is generally corroborated by the regional and laminar LCGU distribution, anatomical, metabolic and functional aspects of cortical architecture are associated.
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  • 36
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    Acta neuropathologica 79 (1990), S. 456-460 
    ISSN: 1432-0533
    Keywords: Rosenthal fibers ; Immunohistochemistry ; Ultrastructure ; Neoplastic and reactive astrocytes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The nature of Rosenthal fibres (RF) was investigated in eight cases each of low-grade astrocytoma and reactive gliosis using immunohistochemical (IH) staining for glial fibrillary acidic protein (GFAP), electron microscopy (EM) and immunoelectron microscopy (IEM) by immunogold labelling technique. By IH under light microscopy (LM), three types of RF were seen, uniformly positive (type I), rim positive (type II) and completely negative (type III). EM showed variation in structural pattern of RF. Some RF contained large amount of glial filaments (GF) intermingled with RF while others with a large amount of electron dense material and less GF. Thus, the presence and amount of GF in RF appear to be responsible for the different types of IH staining under LM. IEM showed that all RF including the ones consisting of entirelh amorphous material possess immunoreactivity for GFAP. It is suggested that RF formation is a two-stage process, staring with excessive accumulation of GF within astrocytic processes followed by their gradual alteration into electron-dense amorphous material under the influence of some unknown metablic or other factors. The quantitative analysis of different types of RF suggests a difference in the rate of formation of RF in neoplastic and reactive conditions.
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  • 37
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    Acta neuropathologica 79 (1990), S. 551-557 
    ISSN: 1432-0533
    Keywords: Cutaneous nerves ; Neuropathy ; Ultrastructure ; Herpesvirus ; Rabbits
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary A light and electron microscopic study was undertaken to determine pathological changes in cutaneous spinal nerves of rabbits following intradermal inoculation with alphaherpesvirus saimiri (αHVS) isolate KM 322. Infected rabbits were killed at 3, 10, 17, 45 days and 2 years after infection. No abnormalities were seen at 3 days postinoculation. In the nerves of the rabbits killed at 10, 17 and 45 days after infection, axonal (Wallerian-type) degeneration was the main pathological feature. Regeneration, manifested by axonal sprouting, was observed in the nerves of the rabbits killed at 45 days post-inoculation. Neural fibrosis and paucity of unmyelinated axons was the final outcome. The severity of the neural damage not only varied according to the progression of the disease but between nerves taken from the same rabbit. This was probably associated with variation in the numbers of virus particles that had reached the dorsal root ganglion of the dermatome served by a particular nerve. Since αHVS (isolate KM 322) provides a model system for the study of virus latency in dorsal root ganglia, and consequently for the study of varicellazoster infection in man, these findings give further insight into the pathology of herpetic neuropathy.
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  • 38
    ISSN: 1432-0533
    Keywords: Focal cerebral ischemia ; Middle cerebral artery ; Rat ; Reperfusion ; 2,3,5-Triphenyl-tetrazolium chloride
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The extent of histochemical change following middle cerebral artery occlusion was quantitatively determined in three groups of Sprague-Dawley rats with 2,3,5-triphenyltetrazolium chloride (a marker of mitochondrial oxidative enzyme function). In group I (n=7) occlusion was maintained for 3 h, with immediate sacrifice. In group II (n=7) occlusion was maintained for 5 h, with immediate sacrifice. In group III (n=7) occlusion was maintained for 3 h, followed by a 2-h period of reperfusion prior to sacrifice. The area of injury was significantly larger (P〈0.05) in the 5-h occlusion group [15±4% (mean±SD)] compared to the 3-h occlusion group (9±2%); indicating a time-dependent worsening of the histochemical detection of injury. However, the area of injury was significantly less in the reperfusion group (5±2%) compared to the group that was evaluated after 3 h of occlusion without reperfusion (9±2%); indicating that some component of the injury revealed by 2,3,5-triphenyltetrazolium chloride is potentially reversible. These data suggest that contrary to previous understanding, the histochemical abnormality revealed by 2,3,5-triphenyltetrazolium chloride is reversible in some circumstances and does not necessarily represent inevitable infarction.
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  • 39
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    Acta neuropathologica 80 (1990), S. 255-259 
    ISSN: 1432-0533
    Keywords: Meningioma ; Phospholipid ; Psammoma ; Ultrastructure ; Chromatography
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Phospholipids in meningiomas were studied by light and electron microscopy, and by high-performance liquid chromatography. They were microscopically demonstrated in six of the ten cases by Sudan III staining after the fixation with potassium dichromate. However, the conventional ultrastructural fixation with glutaraldehyde and osmium tetroxide failed to confirm phospholipids, as most of them were dissolved during dehydration. In contrast, the specimens pretreated with tannic acid before osmication ultrastructurally retained phospholipids which were represented by multilamellar bodies or ribbon-like rings. Both were found in 23 of the 30 cases within the cytoplasm, among the plasma membranes and in the extracellular matrices. The outermost lamella or ribbon showed a direct continuity from the neighbouring plasma membranes of the cytoplasm or the mitochondria. The multilamellar bodies showed an overall distribution, while the ribbon-like rings were predominantly distributed around the psammoma bodies. Precipitation of hydroxyapatite crystals within the ribbon-like rings resulted in matrix minerals of psammoma bodies. Chromatographical analyses of meningiomas disclosed phospholipids including phosphatidyl ethanolamine, phosphatidyl choline, phosphatidyl serine, sphingomyelin and phosphatidyl inositol in that order. Psammomatous meningiomas contained a higher percentage of phosphatidyl serine than non-psammomatous tumors. Ultrastructural study of synthetic phospholipids adequately treated with tannic acid showed that the multilamellar bodies were similar to phosphatidyl choline, while the ribbon-like rings were similar to phosphatidyl serine. The role of phospholipids in meningiomas is discussed.
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  • 40
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    Anatomy and embryology 182 (1990), S. 1-10 
    ISSN: 1432-0568
    Keywords: Fish ; Muscle growth ; Hyperplasia ; Hypertrophy ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary In this EM study of lateral muscle in Dicentrarchus labrax, we observed that during the larval period, growth of the presumptive red and white muscle layers occurs both by hypertrophy (as fibres already present at hatching complete their maturation) and by production of new fibres in germinal zones specific to the two muscle layers. In the first half of larval life the presumptive white muscle increases in thickness by the addition, superficially, of new fibres derived from a germinal zone of presumptive myoblasts lying beneath the red muscle layer. In the second half of larval life new fibres produced in this same zone form the intermediate (or pink) muscle layer. Dorsoventrally the myotome grows throughout larval life, largely by addition of new fibres from germinal zones at the hypo- and epi-axial extremities. Towards the end of larval life all these germinal zones are becoming exhausted, but another source of fibres arises as satellite cells, associated with large-diameter presumptive white muscle fibres, are activated to produce new fibres. The addition of small, new fibres gives the white muscle its mosaic appearance. Morphometric analysis of fibre diameters in the white muscle confirms that whereas these hyperplastic processes are important during the larval and juvenile periods, when growth is very rapid, they have ceased by the time the adult stage is attained. By contrast, fibre hypertrophy continues through into adult life. The presumptive red muscle consists initially of a monolayer of fibres present only near the lateral line, and during larval life it grows hypo- and epi-axially by addition of fibres derived from myoblasts already present in these areas at hatching. Lying superficially to the presumptive red muscle monolayer there is a near-continuous layer of external cells with a “flattened” profile. During the second half of larval life, differentiation of these external cells into myoblasts provides the source of new fibres which are added to the red muscle layer. This process, which occurs initially in the region around the lateral line and later spreads outwards, is responsible for the increase in thickness of the red muscle.
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  • 41
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    Anatomy and embryology 182 (1990), S. 41-52 
    ISSN: 1432-0568
    Keywords: Lamprey ; Pronephros ; Ultrastructure ; Regression ; Apoptosis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The regression of the pronephric kidney of the lamprey, Petromyzon marinus, is described using histochemical and ultrastructural techniques. Regression begins in the third year of larval life, and by the time the animal enters metamorphosis the tubules have all disappeared. The nephrostomes and the renal corpuscle, however, persist for the remainder of the life cycle and undergo little change in the larva. Iron is present within the tubular epithelium prior to the beginning of degeneration, but as degeneration proceeds iron is observed within the tubule lumina. Acid phosphatase is noted within the tubule epithelia prior to degeneration, but as degeneration proceeds acid phosphatase is also observed within the intertubular area. Features of tubular regression include a prominent and highly folded basal lamina, numerous cytoplasmic inclusions, and dense bodies in the epithelia and lumina. The intertubular region is invaded by lymphocytes, granulocytes, plasma cells, and macrophages. The process of pronephric regression possesses many features of the process of apoptosis, which has been noted in the regression of larval organs in other vertebrates.
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  • 42
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    Anatomy and embryology 182 (1990), S. 307-317 
    ISSN: 1432-0568
    Keywords: Rat ; Kidney ; Interstitial cells ; Major histocompatibility complex
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary To study the ontogenetic development of the interstitial tissue of the kidney, rats were investigated 1, 3, 7, 14, 21 and 28 days after birth. Kidneys perfusionfixed with glutaraldehyde were studied with light- and electron microscopy. Cryostate sections from kidneys immediately frozen in liquid nitrogen were studied with respect to the expression of MHC class II antigen using the monoclonal antibody OX6. The interstitial space of both the renal cortex and the outer and inner medulla was prominent during the first days postnatally. The relative interstitital volume of the cortex and outer part of the medulla then decreased in conjunction with the outgrowth and maturation of the superficial nephrons while the inner medullary interstitium remained wide. During the first postnatal days, the abundant interstitial cells of the cortex were connected via cytoplasmic processes to form a loose network which later became less well defined. The lipid-laden interstitial cells of the inner medulla showed essentially the same ultrastructure in the newborn as in the adult animal. Strong expression of class II antigen first appeared on epithelial cells of the thick ascending limb of Henle’s loop about 7 days postnatally, and became weak at 28 days. From 21 days, a weak staining of the proximal tubules was also observed. While interstitial cells in the inner medulla were always negative, cortical and outer medullary interstitial cells became strongly positive for class II antigen from day 21 post partum.
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  • 43
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    Anatomy and embryology 181 (1990), S. 441-452 
    ISSN: 1432-0568
    Keywords: Development ; Pancreatic primordium ; Transplantation ; Immunohistochemistry ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The dorsal pancreatic primordia of 12.5-day-old rat embryos transplanted into the third ventricle of adult female rats were immunohistochemically examined 10, 20 and 40 days after transplantation. On day 10, the grafts grew into an epithelial sacculus (S) with a thick subepithelial tissue (ST). Tubular and vesicular structures with a single cuboidal epithelium were found within the wall of the S, but they underwent thereafter a regression without allowing the primordia to differentiate into the exocrine acinar tissues. In contrast with this, pancreatic hormone-containing cells existed in the ST, and were arranged like the islands of a mature animal. The tissue also has smooth muscle fibers and neurons. When the primordium was grafted along with its root connected to the duodenum, gut-like tubular structures differentiated, showing mucosa with villi and crypts, submucous mesenchymal tissue and muscle layers. The mucosa possesses epithelial cells immunoreactive for the pancreatic hormones, and the muscle layers have the myenteric plexuses. These findings seem to provide further evidence that in the rat pancreas, pancreatic-hormone-containing cells differ from the acinar cells in origin.
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  • 44
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    Anatomy and embryology 181 (1990), S. 491-498 
    ISSN: 1432-0568
    Keywords: Serotonin ; Ultrastructure ; Caudal Neurosecretory Complex ; Neuroendocrine ; Monoamines
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The caudal neurosecretory complex (CNc) of poecilids has previously been shown to receive serotonergic inputs. In the present study, immunohistochemical techniques were applied at the light and electron microscopic levels to characterize serotonergic terminals in the neuroendocrine nucleus. A dense plexus of varicose fibers observed in the rostral CNc neuropil was absent in the spinal cords of deafferented fish, indicating that the origin of this input was extranuclear. Ultrastructural study revealed no direct contacts between labeled structures and neuroendocrine cells. Non-synaptic terminals (varicosities) were the predominantly labeled structures in the neuropil. Synaptic terminals were observed on cellular and axonal targets in the CNc. Small cells containing 70 nm dense-core vesicles received serotonergic input on their perikarya. Labeled synapses were also found on unlabeled axon terminals which made axoaxonal synapses on neuroendocrine processes. Non-synaptic terminals may be responsible for a variety of serotonin-mediated effects in the CNc. Synaptic interactions with local catecholaminergic and afferent cholinergic inputs to the CNc are likely.
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  • 45
    ISSN: 1432-0568
    Keywords: Mandibular condyle ; Articular tissue layer ; Ultrastructure ; Maturation ; Load-dependence ; Macaca fascicularis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary In an attempt to establish maturational alterations in the morphology of the articular tissue layer, mandibular condyles of four immature and four mature male monkeys (Macaca fascicularis) were studied using light microscopy as well as scanning and transmission electron microscopy. Specimens were fixed in situ by perfusion in the presence of ruthenium red to stabilize proteoglycans. Preparations intended for observation in the scanning electron microscope were first dehydrated and sputtered for the examination of articular surfaces, and afterwards treated with trypsin to expose the spatial arrangement of collagen fibrils. Gross anatomical relations between joint components indicated that the anterior and central, but not the posterior region of the condylar articular surface can be subject to compressional load. Load-bearing and non-load-bearing regions differed with respect to the morphology of the articular layer. Load-bearing surfaces were covered by a prominent articular surface lamina similar to that observed on articular cartilage. This lamina seemed to constitute an integral part of the articular layer, distinct from the lining of synovial fluid, and to be composed largely of proteoglycans. It was unaffected by maturation. The subjecent, load-bearing articular layer differed markedly in structure, both from articular cartilage, and between immature and mature animals. Articular cells of immature animals were classified as fibroblastlike, but unlike typical fibroblasts, were surrounded by a thin, often incomplete halo of fibril-free pericellular matrix, presumably consisting of proteoglycans. In mature animals, articular cells closely resembled chondrocytes, but exhibited prominent nuclear fibrous laminae, which usually are found only in fibroblasts. Thus, the load-bearing part of the articular layer seems to undergo a maturation-dependent metaplastic conversion, from a dense connective tissue with some features of fibrocartilage, to a fibrocartilage-like tissue containing chrondrocytelike cells with some features of fibroblasts. This conversion might reflect an adaptation to a maturation-associated increase in articular stress.
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  • 46
    ISSN: 1432-069X
    Keywords: Dysplastic naevi ; Superficial spreading melanoma ; Naevocellular naevi ; Ultrastructure ; Melanosomes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Eleven dysplastic melanocytic naevi with various degrees of dysplasia, as judged by light microscopy, were studied by transmission electron microscopy, and their intra-epidermal melanocytes compared with those of five superficial spreading melanomas and seven common benign naevocellular naevi. Intra-epidermal melanocytes in dysplastic naevi exhibited signs of cellular atypia, which were most pronounced in the dysplastic naevi with histological high-grade dysplasia. A correlation between the degree of dysplasia at the light microscopic level and the degree of cytological atypia at the ultrastructural level was noted, and melanocytes in dysplastic naevi with a high degree of dysplasia had ultrastructural features similar to the melanocytes in superficial spreading melanomas. Our observations support the concept that dysplastic naevi fill the biological gap between benign naevocellular naevi and malignant melanomas and suggest that at least some of the dysplastic naevi must be regarded as potential precursor lesions of malignant melanoma, particularly those exhibiting a high degree of histological dysplasia.
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  • 47
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    Archives of dermatological research 282 (1990), S. 108-114 
    ISSN: 1432-069X
    Keywords: Porphyria ; Dermal vessels ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The skin of 20 patients with variegate porphyria (VP) was studied using light, fluorescent, and electron microscopy. Twelve patients had skin symptoms and markedly increased fecal protoporphyrin excretion. Their sun-exposed skin was characterized by homogeneous PAS-positive thickening and IgG deposition in the vessel walls. The basic ultrastructural change was thickening of the vascular walls caused by reduplication of the basal lamina and perivascular deposition of amorphous material. Qualitatively similar but less prominent histopathological changes occurred in sun-protected skin in some of the patients. Six patients had no skin symptoms but an increased porphyrin excretion. The light microscopical changes were comparable to those in the patients with skin symptoms, but the ultrastructural changes were less severe. No abnormal histopathological changes occurred in two symptomless patients who had low lymphocyte protoporphyrinogen oxidase activity but normal fecal porphyrin excretion. These results show that the primary site of skin damage in VP is the vessel wall, and that histopathological changes of the skin also occur in porphyric patients who have never had skin symptoms. Factors determining the occurrence of skin symptoms in VP are discussed.
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  • 48
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    Archives of dermatological research 282 (1990), S. 434-441 
    ISSN: 1432-069X
    Keywords: Hair cycle ; Human hair follicle ; Connective tissue sheath ; Hyaline membrane ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Ultrastructural changes of the connective tissue sheath (CTS), including the hyaline membrane, of human hair follicles during the hair cycle, were studied in normal scalp skin specimens. In early anagen, the CTS was composed of a thin basal lamina and surrounding collagen tissue. The collagen tissue gradually thickened during the development of the hair and hair follicle. In mature anagen hair follicles, the collagen tissue was separated into three layers. The inner collagen layer, just outside the basal lamina, was thin and composed of collagen fibres running longitudinally parallel to the hair axis. The middle collagen layer was very thick with its collagen fibres running transversely against the hair axis and surrounding the inner hair tissue. Many fibroblasts were present among the collagen fibres in the middle layer, whereas the inner layer contained almost none. In the outer collagen layer, collagen fibres ran in various directions parallel to the outer surface of the outer root sheath cells. In late anagen, the basal lamina became very thick. In catagen, the basal lamine and the inner collagen layer became corrugated and showed oedematous change and degeneration. Surrounding fibroblasts showed active production of new collagen fibres, which seemed to fill the spaces left by the retraction of the hair follicle and hyaline membrane. These ultrastructural changes of the CTS show that there may be dynamic metabolic changes of the connective tissue around human hair follicles during the hair cycle.
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  • 49
    ISSN: 1432-041X
    Keywords: Inner cell mass ; Blastocyst ; Morula ; Implantation ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The number of trophectoderm (TE) and inner cell mass (ICM) cells was determined by complementmediated lysis and differential staining in rat embryos collected at different times during in vivo preimplantation development. At 90 h after fertilization, two groups of morulae were discriminated according to the presence or absence of detectable ICM cells, and the analysis of their total cell number indicated that acquisition of a permeability seal between TE cells begins at the 14-cell stage. On the other hand, our data confirmed that blastocoele formation occurs after the fourth cleavage division in the rat. The total cell number increased exponentially with time in blastocysts recovered between 90 h and 127 h but the cell kinetics of TE and ICM cells were different. The proportion of ICM cells consequently varied throughout blastocyst development, with a peak value for expanded blastocysts at 103 h. Finally, a linear-quadratic relationship was found between the numbers of TE and ICM cells when all the embryos with a detectable ICM were analysed together.
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  • 50
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    Intensive care medicine 16 (1990), S. 436-440 
    ISSN: 1432-1238
    Keywords: Rat ; Pulmonary artery ; Pulmonary hypertension ; Thromboxane B2 ; Prostacyclin ; Prostaglandin F1α ; Endotoxin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract To determine in the rat whether pulmonary artery hypertension accompanies thromboxane release, we sequentially monitored pulmonary and systemic artery pressures and cardiac output. We measured pulmonary and aortic plasma levels of TxB2 as well as 6-keto-prostaglandin F1α (6-keto-PGF1α) in awake unrestrained adult male Sprague-Dawley rats given a single infusion of endotoxin at the relatively high dose commonly administered to this endotoxin-resistant species. At 40 min after endotoxin infusion, both pulmonary and aortic TxB2 and 6-keto-PGF1α levels increased nine-fold and seven-fold above baseline, respectively. In the pulmonary artery, 40 min after infusion, both mediator levels differed significantly from baseline (p〈0.05), whereas in the aorta, because of marked variance in the response of different animals, only the 6-keto-PGF1α levels achieved significance (p〈0.05). These changes were associated with a fall in systemic blood pressure and cardiac output, but no demonstrable rise in pulmonary artery pressure (PAP). Despite ultrastructural evidence of vascular injury, these data indicate that in the rat thromboxane and prostacyclin release following a single infusion of endotoxin is not associated with pulmonary hypertension and that increased prostacyclin production may contribute to systemic hypotension.
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  • 51
    ISSN: 1432-1106
    Keywords: Lateral vestibular nucleus ; 5-hydroxytryptamine ; Microiontophoresis ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary 5-hydroxytryptamine (5-HT) was delivered microiontophoretically (20–80 nA) to cells of the lateral vestibular nucleus of anaesthetized rats to test its influence on the spontaneous activity of single neurons. 5-HT increased the rate of firing of 94% of the units tested. The enhancement persisted for up to 700 s after the end of the 5-HT ejection and the maximum magnitude of the excitation (10–3400%) showed a hyperbolic correlation (ϱ=0.86) with background firing. In 43% of units the enhancement was preceded by a short-lasting (less than 105 s) depression of the neuronal firing rate, the magnitude of which was unrelated to the background mean firing rate. Both components of the 5-HT response were dose-dependent. Only the excitatory responses were antagonized by metergoline, methysergide and ketanserin. The putative 5-HT agonist, 5-methoxy-N,N-dimethyltryptamine, applied microiontophoretically, depressed the background firing rate and was not antagonized by methysergide. These results demonstrate that 5-HT modifies the responsiveness of vestibular neurons and suggest that at least two mechanisms and maybe two types of receptors are activated by 5-HT in this nucleus.
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  • 52
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    Experimental brain research 81 (1990), S. 85-94 
    ISSN: 1432-1106
    Keywords: Spinocerebellar neurons ; Dorsal root projections ; Double labeling ; Choleragenoid ; Fluorogold ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The aim of this study has been to investigate projections to spinocerebellar cell groups from lumbar dorsal root ganglia (DRGs) in the rat. The binding subunit of cholera toxin conjugated to horseradish peroxidase (B-HRP) was used to label primary afferent fibers. Spinocerebellar neurons were labeled retrogradely by Fluoro-Gold (FG). To determine the orientation of dendrites, retrogradely labeled spinocerebellar neurons were studied, following injections of wheat germ agglutinin conjugated horseradish peroxidase (WGA-HRP) into cerebellum. FG or WGA-HRP labeled neurons were found mainly in laminae V and VII, in the lateral group of lamina IX, in Clarke's column (CC) and in the dorsal funiculus. B-HRP labeled primary afferent fibers overlapping with FG labeled cells were observed at all these locations after injections of B-HRP into different DRGs. The overlap in lamina V was found mainly medially and dorsolaterally. CC was found to receive dense projections from DRGs L1–6. In the lumbar part of CC, labeling from DRGs L4–5 overlapped and was distributed over the entire mediolateral extent of the CC, whereas labeling from DRGs L1–3 was somatotopically organized and projected to successively more dorsomedial areas. The central area of lamina VII showed moderate labeling from DRGs L3–5. The lateral group of lamina IX received only smaller amounts of labeled fibers from DRGs L3–5.
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  • 53
    ISSN: 1432-1106
    Keywords: Hypoglossal nucleus ; Catecholamines ; Norepinephrine ; Immunocytochemistry ; Electron microscopy ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary A correlative light and electron microscopic investigation was undertaken to determine the morphology and distribution of catecholamine (CA)-containing axon terminals in the hypoglossal nucleus (XII) of the rat. This was accomplished immunocytochemically with antibody to tyrosine hydroxylase (TH). The major findings in this study were the following: 1) Immunoreactive profiles were found throughout XII and included unmyelinated axons, varicosities, axon terminals and dendrites; 2) Nonsynaptic immunoreactive profiles (preterminal axons, varicosities) were more frequently observed (55.2%) than synaptic profiles (43.5%); 3) CA-containing axon terminals ending on dendrites were more numerous (71.8%) than those synapsing on somata (25.4%) or nonlabeled axon terminals (2.7%); 4) The morphology of labeled axon terminals was variable. Axodendritic terminals typically contained numerous small, round agranular vesicles, a few large dense-core vesicles and were associated with either a symmetric or no synaptic specialization, axosomatic terminals were often associated with a presynaptic membrane thickening or a symmetric synaptic specialization and contained small, round and a few elliptical-shaped vesicles, while axoaxonic synapses formed asymmetric postsynaptic specializations; and 5) CA-positive dendritic processes were identified in XII. These findings confirm the CA innervation of XII, and suggest a complex, multifunctional role for CA in controlling oro-lingual motor behavior.
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  • 54
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    Experimental brain research 81 (1990), S. 209-212 
    ISSN: 1432-1106
    Keywords: NMDA ; Excitatory postsynaptic current ; Voltage sensitivity ; Patch clamp ; Thin hippocampal slice ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Patch-clamp techniques were used to record pharmacologically-isolated N-methyl-D-aspartate-mediated excitatory postsynaptic currents (NMDA-EPSCs) from dentate granule cells in thin rat hippocampal slices. Membrane voltage modulated these EPSCs in two ways. Firstly, depolarization from resting potential enhanced EPSC amplitudes, as expected for a voltage-dependent block by Mg2+ of synaptically activated NMDA receptor channels. Secondly, depolarization markedly prolonged the time course of decay of NMDA-EPSCs in normal and low extracellular Mg2+. Both mechanisms were complementary in establishing a strong dependence between membrane potential and the amount of charge, namely Ca2+, transferred through synaptically activated NMDA receptor channels, that presumably underlies induction of long-term potentiation in the hippocampus.
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  • 55
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    Experimental brain research 81 (1990), S. 346-352 
    ISSN: 1432-1106
    Keywords: Vibrissae representation ; Ventrobasal complex ; Columnar organization ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The region of vibrissae representation in the ventrobasal complex (VB) of the rat was systematically mapped, based on receptive fields of many single neurons. Results showed that the ventralmost row of vibrissae projected to the rostral part of VB, that the dorsal-most row projected to the caudal part, and that the caudalmost vibrissae of each row projected to the most dorsolateral part of VB and more rostral vibrissae to the more ventromedial part. Further, it was revealed that the clusters of neurons receiving projections from any individual vibrissae formed corresponding columns extending from the anterodorsomedial to the posteroventrolateral direction, and that these columns piled up dorsoventrally and anteroposteriorly, with ventral ones shifted progressively medially. When cross sections of these columns were viewed on an oblique horizontal section of VB, a group of columns corresponding to each row lined up from the dorsolateral to the ventromedial direction with a rostral convexity, which means that the third or fourth vibrissa in each row projected most rostrally in that row. These results confirmed previous physiological mapping studies of vibrissal representation and are in good agreement with anatomical studies on barreloid structure in VB.
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  • 56
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    Experimental brain research 81 (1990), S. 313-317 
    ISSN: 1432-1106
    Keywords: Valproic acid ; Ionic currents ; Cerebral cortex ; Patch clamp ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Rat neocortical neurons in culture were subjected to the whole cell mode of voltage clamping under experimental conditions designed to study Na+, Ca{2su+} and K+ currents in isolation. Following pharmacological blockade of most of the Ca2+ and K+ channels, depolarizing commands which brought the membrane potential from — 80 to +10 mV elicited an inward current. This current was sensitive to tetrodotoxin (TTX) and was therefore caused by the opening of voltage-dependent channels permeable to Na+. Extracellular application of the antiepileptic drug valproic acid (VPA, 0.2–2mM) reduced in a dose-related, reversible way this Na+ current. VPA also evoked an increase of the voltage-dependent inward current recorded in the presence of TTX and thus presumably carried by Ca2+; this effect was seen in the presence of doses of VPA larger than 0.5 mM and was not reversible. Two types of outward K+ currents evoked by depolarizing steps in the presence of Na+ and Ca2+ channels blockers were not affected by VPA (up to 5 mM). Our data indicate that doses of VPA that are within the range present when it is used as an anticonvulsant, can influence inward currents generated by rat neocortical cells in culture. The reduction of the Na+, inward current is in line with findings obtained in mouse neurons by using standard intracellular recording techniques. This effect might represent an important mechanism of action for VPA in neocortex.
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  • 57
    ISSN: 1432-1106
    Keywords: CGRP ; Motoneurons ; Spinal cord ; Immunocytochemistry ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The expression of Calcitonin gene-related peptide (CGRP) has been demonstrated in motoneurons of several species. We have investigated in adult rats the influence of transection of the spinal cord on CGRP immunoreactivity of motoneurons located below the section. Quantative analysis has been performed with computer-assisted image analysis. As early as 48 h after the section, CGRP immunoreactivity is modified, and the reduction is maximal after one month. Then, both the number of immunoreactive cells and the intensity of staining increase until the 5th month. It is concluded that the expression of CGRP is under the influence of supraspinal afferents to the motoneuron.
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  • 58
    ISSN: 1432-1106
    Keywords: Superior colliculus ; Electrophysiology ; Tectal efferents ; Cuneiform nucleus ; Predorsal bundle ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Neuroanatomical studies have demonstrated that the two major descending pathways from the superior colliculus arise from regionally segregated, distinct, cells of origin. Stimulation and lesion studies have implicated the crossed descending tecto-reticulo-spinal projection in approach movements towards novel stimuli whereas the ipsilateral pathway appears to be involved in the control of avoidance and escape-like behaviours. The present electrophysiological study attempted to characterise the sensory properties of antidromically identified cells of origin of these pathways in anaesthetised rats. We found that the contralaterally projecting predorsal bundle (PDB) efferents were primarily somatosensory while the ipsilateral cuneiform (CNF) projection was primarily visual. PDB cells, mainly found in the intermediate layers, responded principally to vibrissal stimulation with their overlying visual fields optimally stimulated by small dark moving objects in the lower rostral and lateral field. In contrast, most CNF cells were located rostromedially, with the greatest contribution from visual cells responsive to stimuli in the upper rostral field. A significant proportion of these showed no response to small moving dark discs but fired vigorously to ‘looming’ stimuli. Ethological considerations suggest that these are appropriate stimulus characteristics for a system controlling approach and avoidance behaviour in an animal such as the rat where predators generally appear from above and prey is found on the ground.
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  • 59
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    Experimental brain research 82 (1990), S. 606-616 
    ISSN: 1432-1106
    Keywords: Hippocampus ; Medial frontal cortex ; Solitary nucleus ; Horseradish peroxidase ; Antidromic activation ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The hippocampus has previously been shown to influence cardiovascular function, and this effect appears to be mediated by the connection the hippocampus has with the infralimbic area of the medial frontal cortex (MFC), a region which projects directly to the nucleus of the solitary tract (NTS) in the dorsal medulla. In the present study, anatomical and electrophysiological techniques were utilized to determine the degree of convergence of hippocampal input to the MFC on neurons in the MFC which project to the NTS. Injections of the anterograde and retrograde neuroanatomical tracer wheatgerm agglutinin-horseradish peroxidase (WGA-HRP) into the NTS retrogradely labelled cells in the infralimbic and prelimbic regions of the MFC. Injections of WGA-HRP into the ventral hippocampus anterogradely labelled terminals in the MFC which, at the light microscopic level, closely overlapped the origin of the descending projection from the MFC to the brainstem. Electron microscopic analysis revealed that anterogradely labelled terminals make synaptic contact primarily on dendritic processes in the neuropil adjacent to retrogradely labelled cells. In addition, anterogradely labelled terminals did, in some cases, make synaptic contact on the somas of retrogradely labelled cells. Electrical stimulation of the NTS antidromically activated cells in the infralimbic and prelimbic areas of the MFC. The average latency of antidromic activation was 30 msec, corresponding to a conduction velocity of approximately 0.7 m/s. Electrical stimulation of the ventral hippocampus orthodromically activated cells in the MFC. With an appropriate delay between the hippocampal and NTS stimuli, the orthodromic and antidromic potentials could be made to collide. The results of this study establish a structural as well as functional link between the hippocampus and NTS-projection neurons in the MFC.
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  • 60
    ISSN: 1432-1106
    Keywords: Caudate-putamen ; 6-hydroxydopamine ; Dopamine receptor ; choline acetyltransferase ; in situ hybridization ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary In situ hybridization was used to study dopamine D2 receptor (D2R) and choline acetyltransferase (ChAT) mRNA expression in neurons of the rat forebrain, both on control animals and after a unilateral 6-hydroxydopamine (6-OHDA) lesion of midbrain dopamine neurons. D2R mRNA expressing neurons were seen in regions which are known to be heavily innervated by midbrain dopamine fibers such as caudate-putamen, nucleus accumbens and olfactory tubercle. ChAT mRNA expressing neurons were seen in caudate-putamen, nucleus accumbens and septal regions including vertical limb of the diagonal band. In caudate-putamen, approximately 55% of the medium sized neurons, which is the predominating neuronal cell-size in this region, were specifically labeled with the D2R probe. In addition, approximately 95% of the large size neurons in caudate-putamen were specifically labeled with both the D2R and ChAT probes, suggesting that most cholinergic neurons in the caudate-putamen express D2R mRNA. After a unilateral lesion of midbrain dopamine neurons, no change in the level of either D2R or ChAT mRNA were seen in the large size intrinsic cholinergic neurons in caudate-putamen. Similarily, no evidence was obtained for altered levels of D2R mRNA in medium size neurons in medial caudate-putamen, or nucleus accumbens. However, an increase in the number of medium size neurons expressing D2R mRNA was observed in the lateral part of the dopamine deafferented caudateputamen. Thus, it appears that midbrain dopamine deafferentation causes an increase in D2R mRNA expression in a subpopulation of medium size neurons in the lateral caudate-putamen.
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  • 61
    ISSN: 1432-1106
    Keywords: Swallowing ; Nucleus tractus solitarius ; Excitatory amino acids ; Ketamine anesthesia ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Swallowing is a patterned motor activity generated by neurons located within the nucleus tractus solitarius (NTS). An excitatory amino acid (EAA) neurotransmitter, such as glutamate (GLU), is suspected of being involved in the initiation of swallowing by NTS neuronal components. However, swallowing can still be elicited in animals anesthetized with ketamine, an antagonist of the N-methyl-D-aspartate (NMDA) subclass of EAA receptors. The present experiments were therefore designed to investigate the influence of EAA administration within the NTS on the swallowing motor acitivity of rats anesthetized with ketamine. Pressure microinjections of GLU in doses ranging from 25 to 500 pmol elicited swallowing. This effect was dose-dependent and was not reproduced when control injections of the vehicle solution were performed. Microinjections of the GLU agonists, quisqualate (QUIS) and NMDA, in doses ranging between 2.5 and 50 pmol, also induced swallowing motor activities. QUIS, like GLU, elicited a short series of swallows at a brief latency while NMDA generated long-lasting rhythmic swallowing with a longer latency. Swallowing induced by GLU microinjections (100 pmol) was suppressed almost completely by local pretreatment with either the broad spectrum EAA receptor antagonist, gamma-D-glutamylglycine (250 pmol), or the more selective non-NMDA antagonist, 6-cyano-7-nitroquinoxaline-2,3-dione (50–100 pmol), but not by pretreatment with the selective NMDA antagonist, DL-2-amino-5-phosponovalerate (250 pmol). On the other hand, pretreatment with DL-2-amino-5-phosphonovalerate (50 pmol) suppressed the deglutitions induced by NMDA microinjections (10 pmol) but not those elicited by QUIS microinjections (10 pmol). These results provide evidence that swallowing can be induced by activation of EAA receptors of both the NMDA and the non-NMDA subclasses located within the NTS. Furthermore they indicate that both subclasses may still be active in ketamine-anesthetized animals.
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  • 62
    ISSN: 1432-1106
    Keywords: Synaptic transmission ; Excitatory amino acids ; NMDA receptor antagonists ; Hippocampal formation ; Long-term potentiation ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary NMDA receptor antagonists produced differential effects on medial and lateral perforant path-evoked excitatory postsynaptic potentials (EPSPs) recorded in the dentate gyrus molecular layer of hippocampal slices. D-(-)-2-amino-5-phosphonovaleric acid (D(-)APV) and 3-[(±)-2-carboxypiperazin-4-yl]-propyl-1-phosphonic acid (CPP) significantly reduced the peak amplitude and total area, but not the initial negative slope, of the medial perforant path-evoked EPSP. Neither antagonist affected any component of the lateral perforant path-evoked EPSP. In contrast, population spikes evoked by stimulation of either pathway were depressed.
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  • 63
    ISSN: 1432-1106
    Keywords: Sleep ; Voltammetry ; High performance liquid chromatography (HPLC) ; Serotonin (5-HT) ; 5-hydroxyindoleacetic acid (5-HIAA) ; Corticotropin-like intermediate lobe peptide (CLIP) ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary In the present work, differential pulse voltammetry (DPV) measurements of the extracellular fraction of 5-hydroxyindole compounds were performed in rats under long-term chronic conditions. In the nucleus Raphe Dorsalis (n.RD), the voltammetric signal measured at +300 mv (peak 3) disappeared completely 70 to 90 min after injection of Clorgyline (10 mg/kg), a monoamine oxidase inhibitor type A (MAOI-A); the signal measured in such conditions is thus dependent upon extracellular 5-hydroxyindoleacetic acid (5-HIAA peak 3). Deprenyl, an MAOI type B, at the same dose, induced only a slight increase in peak 3 height; according to the fact that MAO-B is selectively located in the 5-HT neurons and since their inhibition does not decrease 5-HIAA peak 3 nor the endogenous 5-HIAA content as measured with High Performance Liquid Chromatography (HPLC), 5-HIAA measured with DPV in the extracellular fluid of untreated animals might come from 5HT released and metabolized by MAO-A outside the 5-HT neurons. In animals implanted for measurements of both voltammetric and polygraphic parameters, the 5-HIAA peak 3 measured mainly in the anterior and ventral part of the n.RD exhibited large increases in its height during slow-wave sleep (SWS: +39%) and paradoxical sleep (PS=+71%) as compared to the waking state (W=100%); these variations could reflect the dendritic release of 5-HT. In the Caudate nucleus (n.Cd) the same voltammetric signal presented reverse fluctuations, i.e. an increase during W and a decrease during SWS and PS. Intracerebroventricular administration of Corticotropin-Like Intermediate lobe Peptide (CLIP, 10 ng/2 μl) induced an increase in PS duration (+51%) preceded and accompanied by an increase in the n.RD 5-HIAA peak 3 height (+50%).
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  • 64
    ISSN: 1432-1106
    Keywords: 6-hydroxydopamine ; Neonatal ; Dopamine ; D1 receptors ; Dopamine D2 receptors ; Cyclic adenosine 3′∶5′-monophosphate ; Adenylate cyclase ; DARPP-32 ; Nonlinear curve fitting ; Random-effects ; model ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Newborn male Sprague-Dawley rats were treated neonatally with an intracisternal injection of 75 μg 6-hydroxydopamine (6-OHDA) following desipramine pretreatment in order to induce a permanent selective dopamine (DA) lesion. At 60–70 days of age a massive loss of tyrosine hydroxylase (TH) immunoreactive (IR) cells was seen in substantia nigra. The TH-IR terminal density was reduced by 92% in striatum, 77% in nucleus accumbens and by 72% in tuberculum olfactorium. Quantitative autoradiography using 3H-SCH-23390 and 3H-spiperone did not reveal any alteration of DA D1 and D2 receptor binding in the denervated regions studied. Furthermore, no change in the Bmax or Kd of 3H-SCH-23390 or 3H-spiperone in vitro binding was observed in membrane preparations of striatum following the neonatal DA lesion. Basal and DA-stimulated accumulation of cAMP was increased in striatal membrane preparations of the neonatally DA-lesioned rats. No alteration of the immunoreactivity of the D1 receptor associated phosphoprotein dopamine- and adenosine 3′∶5′-monophosphate-regulated phospho-protein (DARPP-32), was observed as visualized using quantitative immunohistochemistry. Thus, neonatal DA lesions seem to induce a selective functional supersensitivity reflected by an enhanced activity of D1 receptor-coupled adenylate cyclase, without any alteration in the number or affinity of D1 and D2 receptor sites. Further-more, the appearance of DARPP-32 seems to be independent of intact DA input during development.
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  • 65
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    Experimental brain research 80 (1990), S. 532-544 
    ISSN: 1432-1106
    Keywords: Frontal cortex ; Frontal eye fields ; Reticular formation ; Brain stem ; Preoculomotor nuclei ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Projections from medial agranular cortex to brain stem in rat were determined by use of the anterograde tracers Phaseolus vulgaris leucoagglutinin, or wheat germ agglutinin conjugated horseradish peroxidase. Axonal trajectories were also followed by means of the Wiitanen modification of the Fink-Heimer degeneration technique. AGm was identified on the basis of its cytoarchitectonics. AGm projected to the anterior pretectal nucleus, the rostral interstitial nucleus of the medial longitudinal fasciculus, the medial accessory oculomotor nucleus of Bechterew, the interstitial nucleus of Cajal, the nucleus of Darkschewitsch, the nucleus cuneiformis and subcuneiformis, intermediate and deep superior collicular layers, the paramedian pontine reticular formation (reticularis pontis oralis and caudalis, and reticularis gigantocellularis), and raphe centralis superior. Differences in connections between rostral and caudal injections were observed: pontine and medullary projections were lighter from the rostral portion of AGm than from the more caudal portions of AGm. The heaviest projections to the anterior pretectal nucleus were from the caudal portion of AGm. The subcortical projections were very similar to those described for the frontal eye field in monkeys, and the majority of them targeted areas thought to be involved in coordination of gaze with head and neck movements. Thus AGm in rats may contain the homologue of the primate frontal eye fields.
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  • 66
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    Experimental brain research 80 (1990), S. 621-625 
    ISSN: 1432-1106
    Keywords: Binding ; GABAA-sites ; GABAB-sites ; Tissue culture ; Cerebellum ; Brain stem ; Spinal cord ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The cellular localization of GABA-binding sites was studied in explant cultures of rat cerebellum, brain stem and spinal cord by means of autoradiography. Labelling of GABAB-sites was done with 3H(-)baclofen or 3H-GABA in presence of unlabelled bicuculline. Binding sites for these radio-ligands were found on many neurones and on a large number of astrocytes. Labelling of glial cells was usually weaker than that of neurones. Combining autoradiography with staining with anti-glial fibrillary acidic protein (GFAP) revealed that the glial cells labelled with 3H-baclofen or 3H-GABA were GFAP-positive. In contrast, when GABAA-sites were localized using 3H-GABA in presence of unlabelled baclofen, the GABAA-agonists 3H-muscimol and 3H-THIP, or the antagonist 3H-(+)-bicuculline, binding only occurred to neurones but not to astrocytes. Immunohistochemical investigations with the monoclonal antibody (bd-17) against the GABAA/benzodiazepine/chloride channel complex revealed that neurones were specifically stained whereas glial cells were immunonegative. From our observations it is suggested that astrocytes possess GABAB-receptors but there is little evidence for the existence of GABAA-sites on glial elements.
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  • 67
    ISSN: 1432-1106
    Keywords: NMDA receptor ; Quisqualate/kainate receptor ; Excitatory amino acid ; Medial vestibular nucleus ; Slice ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The actions of excitatory amino acid (EAA) antagonists on synaptic inputs to neurons in the rat medial vestibular nucleus (MVN) from ipsilateral vestibular afferents and vestibular commissures were studied in brain stem slice preparations. Antagonists used were 2-amino-5-phosphonovalerate (APV), a selective antagonist for the N-methyl-D-aspartate (NMDA) type of EAA receptors, 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX), a selective antagonist for the quisqualate/kainate (non-NMDA) type of EAA receptors and kynurenate (KYNA), a broad spectrum antagonist for the three types of EAA receptors. MVN neurons were classified as having mono- or polysynaptic inputs from vestibular afferents and commissural fibers by calculating synaptic delay. An application of APV through the perfusion medium suppressed 82% of cells activated monosynaptically from commissures, while it suppressed only 9% of cells activated monosynaptically from vestibular afferents. The application of KYNA proved much less selective, suppressing 83% of the former group of cells and 93% of the latter. CNQX suppressed almost all the cells of both groups. The sensitivity of monosynaptic inputs to KYNA, CNQX or APV was not significantly different from that of polysynaptic inputs irrespective of sources of inputs. These results suggest that excitatory synaptic inputs to MVN neurons are mediated mainly through non-NMDA type of EAA receptors from vestibular afferents and through NMDA as well as non-NMDA types of EAA receptors from commissures.
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  • 68
    ISSN: 1432-1106
    Keywords: Dynorphin ; Substance P ; Neurokinin A ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The striatonigral pathway contains several neurotransmitters which may regulate the activity of the nigrostriatal dopamine projection in the rat. This was investigated by measuring extracellular dopamine levels in the striatum, using microdialysis, after injections of GABA (300 nmol/0.2 μl), dynorphin A (0.5 nmol/0.2 μl), substance P (0.07 mnol/0.2 μl) or neurokinin A (0.09 nmol/0.2 μl) into the ipsilateral substantia nigra, pars reticulata (SNR). Intranigral injections of GABA or dynorphin A inhibited, while intranigral injections of substance P or neurokinin A stimulated dopamine levels in the ipsilateral striatum. In rats with ibotenic acid lesions (2.5 μg/0.5 μl) in the SNR, intranigral injections of GABA or dynorphin A inhibited, while intranigral injections of substance P or neurokinin A stimulated dopamine levels in the ipsilateral striatum. These responses were not significantly different than those in unlesioned rats. Analysis of the intranigral lesion with in situ hybridization revealed a heavy loss of glutamic acid decarboxylase mRNA expression in the SNR and a significant loss of tyrosine hydroxylase (TH) mRNA expression in the SNC. Immunohistochemical analysis revealed a disappearance of TH-Like immunoreactivity (LI) im dendrites in the SNR, a considerable loss of TH-LI cell bodies in the SNC and a restricted loss of neuropeptide K-LI in the SNR around the tip of the injection cannula. Furthermore, lesioned rats rotated ipsilateral to the lesion after apomorphine (1 mg/kg, s.c.), indicating that the basal ganglia output mediated via the SNR GABA neurons was impaired on the lesioned side. Analysis of the striatum revealed that a dense TH-LI fiber network could still be seen on the lesioned side. Furthermore, basal and amphetamine stimulated extracellular dopamine levels in the striatum on the lesioned side were not significantly depleted. This indicates that the ascending nigrostriatal dopamine projection was functionally intact on the lesioned side. These findings indicate that intranigral GABA, dynorphin A, substance P and neurokinin A modulation of ipsilateral striatal dopamine release is mediated via direct action on the nigrostriatal projection. Thus, it is suggested that the striatonigral pathway, which contains GABA, dynorphin, substance P and neurokinin A, exerts a direct regulatory effect on the activity of the nigrostriatal dopamine projection.
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  • 69
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    Experimental brain research 82 (1990), S. 401-407 
    ISSN: 1432-1106
    Keywords: Cerebellum ; Development ; Graft ; Structure ; Purkinje cell ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary A prominent feature of the mammalian cerebellum is its organization into parasagittal compartments. One marker of such compartments is the zebrin I molecule that is expressed by bands of Purkinje cells (PC). In order to understand better the basis for the development of this organization, we have transplanted dissociated rat cerebellar anlage, taken during the period of proliferation of PC precursors, into kainic acid lesioned adult rat cerebellum. As previously observed, the resultant grafts exhibited trilaminar structures reminiscent of the normal cerebellum. In every case, the PC in the resultant grafts were organized into zebrin I + and — compartments. In one case, most of the grafted PC were integrated into a region of PC deficient host molecular layer that was induced by pretreatment with kainic acid. Clear bands defined by zebrin I reactivity were seen where groups of the grafted PC had entered the host molecular layer. These bands did not correlate in distribution or size with host bands. Hypotheses compatible with these findings that involve specific and non-specific aggregation of PC are discussed.
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  • 70
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    Experimental brain research 82 (1990), S. 456-458 
    ISSN: 1432-1106
    Keywords: HRP histochemistry ; Whole-brain preparations ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Subsequent to eye injections of horseradish peroxidase (HRP) ‘whole-brain’ preparations with only the cortex removed were reacted for HRP using tetramethylbenzidine (TMB) as the chromogen and ammonium heptamolybdate (AHM) as a stabilizer. Retinal projections could be photographed and visualized globally coursing across the surface of the thalamus and midbrain. The brains were then sectioned, and when necessary re-reacted, enabling a 3-D reconstruction of retinofugal pathways to be made.
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  • 71
    ISSN: 1432-1106
    Keywords: Sympathetic nerve ; Superior cervical ganglion ; Cerebral arteries ; Wheat germ agglutininhorseradish peroxidase (WGA-HRP) ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary To clarify the projection route and the expansion of the terminal plexus of the sympathetic nerve fibers innervating the cerebral arterial system in rat, we labeled the postganglionic fibers originating in the superior cervical ganglion and traced their entire course by anterograde labeling with wheat germ agglutinin-horseradish peroxidase. Sympathetic innervation of the internal cerebral artery by labeled fibers actually began just at the portion where it enters the intradural space, and innervated it up to the small pial arteries located in the subarachnoid space, but not the intracerebral arterioles. On the main arteries in the circle of Willis, bundles of nerve fibers ran parallel to the long axis of the vessels and branched perpendicularly their terminal twigs with regular intervals to form a rib-structure pattern. On the arterial branches derived from the circle of Willis, a fine nerve bundle and delicate terminal axons formed a meshwork instead of a rib-structure pattern. These observations confirmed the existence of differences in the distribution pattern of the nerve plexus, which strongly affects the strength and quality of vasoconstriction by sympathetic activation in each level of the cerebral arterial system.
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  • 72
    ISSN: 1432-1106
    Keywords: Neural explants ; Catecholaminergic neurons ; Basal ganglia ; Brainstem ; Neural development ; Tyrosine hydroxylase ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Tissue slices of rat ventral mesencephalon (VM), striatum, hippocampus and cerebellum were prepared from late fetal (E21) to 7 day old (P7) rats and cultured for 3 to 60 days by the roller tube technique before they were stained immunocytochemically for tyrosine hydroxylase (TH), a marker of dopaminergic (DA) neurons and fibres. The TH immunoreactive (TH-i), DA neurons retained their morphological in vivo characteristics in the VM slice cultures consisting of the substantia nigra (SN) and the ventral tegmental area (VTA). The general morphology of the described neuronal cell types did not appear to change when the VM slices were cocultured with striatal tissue, a major normal target of the DA neurons, but an extensive innervation of the striatum by TH-i nerve fibres was observed. In co-cultures of VM and hippocampus, a minor target organ of DA fibres, growth of TH-i nerve fibres was observed mainly into the opposing edge of the hippocampal slice. In co-cultures of VM and cerebellum, which is normally devoid of DA fibres, no significant growth of TH-i nerve fibres into the cerebellar slices was observed. Besides suggesting a target orientated growth of ventral mesencephalic DA fibres, the results point to the further use of VM slice cultures in the study of the developmental, plastic and regenerative properties of DA neurons.
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  • 73
    ISSN: 1432-1106
    Keywords: Somatostatin ; NADPH diaphorase ; Deafferentation-somatosensory cortex ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Recent studies in the developing cortex have shown that during the first 2 postnatal weeks somatostatin (SRIF)-containing neurons appear in greater numbers. After this time their numbers decline significantly probably due to cell death (Cavanagh and Parnavelas 1988). In this study we report changes in the distribution of SRIF-labelled cells in the somatosensory cortex of adult rats following unilateral lesions of mystacial vibrissae at birth. Specifically, we observed that the side contralateral to the lesion contained a significantly greater number of labelled cells compared to the ipsilateral side. We suggest that the decline in cell numbers observed during normal development is reduced following early deafferentation.
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  • 74
    ISSN: 1432-1106
    Keywords: Ischemia ; Neuronal death ; Dopamine ; Striatum ; Mesostriatal system ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Transient periods of global cerebral ischemia lead to selective neuronal damage in the striatum. We investigated the effects of unilateral 6-hydroxydopamine lesions of the mesostriatal dopamine (DA) system on the density and distribution of neuronal necrosis in the rat striatum following ischemia induced by bilateral occlusion of the common carotid arteries combined with hypotension. After both 12 and 15 min of ischemia, which caused slight and extensive striatal damage, respectively, there was no difference in the density of neuronal necrosis in the striatum between DA-lesioned and shamoperated animals. We conclude that the DA system alone does not modulate injury following complete cerebral ischemia, but may contribute significantly to damage following conditions such as during hypoglycemia and incomplete cerebral ischemia.
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  • 75
    ISSN: 1432-1106
    Keywords: Mesencephalic trigeminal nucleus ; Astrocytes ; GFAP ; Primary afferent neurons ; Immunocytochemistry ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The arrangement between astrocytes and the primary afferent neurons of the mesencephalic trigeminal nucleus (Me5) was analyzed in a light and electron microscopy immunocytochemistry study using anti-GFAP antibodies. It appears that each Me5 neuron is almost entirely sheathed with astrocytic processes radiating out from two or more astrocytes. Ultrastructural observations confirmed the embracement of Me5 neurons by astrocytic processes that only allowed some synaptic contacts on the neuronal surface. The possible functional significance of this intimate morphological relationship for the mesencephalic trigeminal neurons is discussed.
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  • 76
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    Experimental brain research 79 (1990), S. 383-387 
    ISSN: 1432-1106
    Keywords: Forskolin ; VIP ; Adenylate cyclase ; Caudate-putamen ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Vasoactive intestinal polypeptide (VIP) was incubated in an adenylate cyclase assay with a particulate fraction of caudate-putamen (CP) tissue of the rat in order to examine the effect of the peptide on forskolin-activated adenylate cyclase in vitro. Forskolin induced an enhancement of cyclic AMP formation that was mediated by an effect on catalytic subunit and stimulatory guanine nucleotide regulatory protein (Ns). In our preparation, VIP did not influence basal adenylate cyclase activity or the stimulation by dopamine and sodium fluoride but, in the absence of guanylylimidodiphosphate (guanosine 5′-(β,y-imido)-triphosphate) VIP inhibited the forskolin-stimulation of the enzyme in a noncompetitive manner. Met-encephalin, acting on a D-2 receptor-coupled putative inhibitory guanine nucleotide regulatory protein (Ni), inhibited the adenylate cyclase activity stimulated by forskolin to a slightly greater extent than VIP. When assayed together, these inhibition effects were additive, implying that the peptide receptors are not identical. The Ni — antagonist, MnCl2 completely blocked the inhibition of met-encephalin but had no significant effect on VIP-induced inhibition. In addition, pertussis toxin did not influence the effect of VIP on forskolin-stimulation in contrast to cholera toxin which did antagonize the VIP effect via the stimulatory guanine nucleotide regulatory protein (Ns). Furthermore, specific D-1 and D-2 dopaminergic receptor antagonists α(+)-flupentixol and spiperone had no effect on VIP-modulated forskolin-stimulated adenylate cyclase activity. These results suggest that the neuromodulatory effect of VIP is mediated by a Ns distinct from those involved in several adenylate cyclase pools sensitive to stimulation by dopamine and VIP in the rat striatum.
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  • 77
    ISSN: 1432-1106
    Keywords: Vestibular nuclei ; Spinal ganglia ; Retrograde tracing ; Wheat germ agglutinin-horseradish peroxidase conjugate (WGA-HRP) ; Neck afferents ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Wheat germ agglutinin-horseradish peroxidase conjugate (WGA-HRP) was microiontophoretically injected into the vestibular nuclear complex of the rat. Retrogradely labeled neurons were found in ipsilateral spinal ganglia C2-C3 only if the injection site was in the caudal part of the medial vestibular nucleus (MVN). Injections into rostral parts of the MVN, the superior, lateral and descending vestibular nuclei (SVN, LVN, DVN), the nucleus of the solitary tract (STN) and the reticular formation did not result in spinal ganglion labeling. Thus, the caudal part of the MVN appears to be the main vestibular termination site for rostral cervical primary afferents.
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  • 78
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    Experimental brain research 79 (1990), S. 436-440 
    ISSN: 1432-1106
    Keywords: Nucleus tractus solitarius ; Slice preparation ; Bursting activity ; Pattern generation ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Extracellular recordings of the activity of nucleus tractus solitarius (NTS) neurons were performed on rat brainstem slice preparations. Neurons localized in the medial part of the lateral NTS, which displayed a synaptic response to single pulse stimulation of the tractus solitarius (TS), generated bursting activity following repetitive TS stimulation (20–50 Hz frequency, 100–600 ms duration). According to their patterns of discharge and to the duration and frequency of their bursting activities, these neurons were classified in three groups called type A, B and C. We suggest that different cellular intrinsic properties, rather than local synaptic interactions, might be involved in the generation of these three types of bursting activities. These results are discussed in terms of the role of NTS neurons in the generation of the swallowing motor pattern.
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  • 79
    ISSN: 1432-1106
    Keywords: Histidine decarboxylase ; Histaminergic neurons ; Substance P ; Synaptic interaction ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The synaptic connections between histaminergic neurons and substance P (SP) afferents in the caudal magnocellular nucleus (CM) of the hypothalamus were examined using an immunoelectron microscopic mirror method. SP-immunoreactive (SP-IR) terminals made synaptic contacts with the somata, somatic spines and dendrites of histidine decarboxylase immunoreactive (HDC-IR) neurons. This suggests that SP afferents exert monosynaptic influence on the central histaminergic neuronal system.
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  • 80
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    Experimental brain research 80 (1990), S. 213-217 
    ISSN: 1432-1106
    Keywords: Visual system ; Auditory system ; Developmental cell death ; Retrograde transport ; Diamidino yellow ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The fluorescent dye diamidino yellow was injected into parts of the developing visual and auditory systems in the rat. The dye was retrogradely transported by projecting neurones and was found to stain pyknotic profiles within the labelled cell populations. It is thus possible to visualize directly the death of neurones which project axons to specific and identified target regions within the nervous system.
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  • 81
    ISSN: 1432-1106
    Keywords: Cyclic AMP ; dl-Propranolol ; Wake-sleep cycle ; Preoptic region ; Hypoxia ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The short-term effects of the intraperitoneal administration of dl-propranolol on the wake-sleep cycle of the rat were studied in relation to the cyclic AMP concentration in the preoptic region and cerebral cortex. The results show that propranolol, but not saline, affected all stages of the wake-sleep cycle, increasing wakefulness, decreasing synchronized sleep and abolishing desynchronized sleep. These effects were associated with a decrement in cyclic AMP concentration both in wakefulness and synchronized sleep. However, this decrement was relatively larger in the preoptic region than in the cerebral cortex. The effects of the drug on cyclic AMP accumulation were also studied in hypoxia, a condition of unspecific brain stimulation. In this condition, the cyclic AMP concentration in both brain regions was found to be higher than that observed during either wakefulness or synchronized sleep. In the hypoxic condition propranolol was found to decrease the nucleotide concentration to the same levels observed in wakefulness and synchronized sleep following its administration. However, no difference in the relative magnitude of the decrement was found between the preoptic region and the cerebral cortex. These findings suggest that in both brain regions the drug acts on a cyclic AMP accumulating system, which may be defined as propranololsensitive. The activity of the propranolol-sensitive system in the preoptic region would appear to be related to wake-sleep processes.
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  • 82
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    Experimental brain research 82 (1990), S. 199-207 
    ISSN: 1432-1106
    Keywords: Serotonin ; Hippocampus ; Feed-forward inhibition ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Serotonin modulating effects on hippocampal electrical activity were studied using serotonin releasing drugs (e.g. d-fenfluramine, FFA, and p-chloroamphetamine, PCA). FFA and PCA enhanced the reactivity of the dentate gyrus to stimulation of the perforant path (PP) in the anesthetized rat. The population spike (PS) but not the population EPSP (EPSP) was enhanced by FFA indicating that the drug effect is not exerted at the PP synapse, but at some postsynaptic site between the synapse and the spike generation mechanism. A depth profile of the response to PP stimulation indicated that the largest effect of FFA was present just below the granular cell layer. There were no systematic effects of FFA on the EPSP at any depth tested. The effect of FFA was much reduced in rats depleted of serotonin by p-chlorophenylalanine (PCPA) and restored when serotonin stores were repleted by the serotonin precursor 5-hydroxytryptophane (5-HTP). d-FFA was at least twice as effective as 1-FFA in enhancing responses in the dentate gyrus (DG). In noradrenaline (NA) depleted rats the increase in PS size was as in control rats. The effects of FFA were blocked by the 5-HT1a antagonist spiperone but not by the 5-HT2 antagonist mianserin. These results suggest that the effect of FFA is primarily due to release of serotonin from its terminals. At the gross electrographic level, FFA suppressed spontaneous sharp wave activity and reduced the magnitude of hippocampal EEG. Spontaneous extracellular single unit activity, recorded in the DG, was also inhibited by FFA concomitantly with the increase in the PS size. FFA did not affect paired-pulse depression. Transection of the commissural connection to the hippocampus (stimulation of which elicits feed forward inibition) markedly attenuated the effects of FFA. It is suggested that serotonin exerts a dual effect on DG granule cells; it suppresses spontaneous activity while enhancing excitability to afferent stimulation. Possibly, the effects of serotonin are exerted by modulation of commissural feed-forward inhibition.
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  • 83
    ISSN: 1432-1106
    Keywords: Epileptic brain damage ; Excitatory amino acids ; Status epilepticus ; Substantia nigra ; SN ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary We have developed a model system in which the mechanisms of neuronal damage due to hyperexcitation can be studied in isolation and where extended observation periods can be used. Substantia nigra pars reticulata (SNPR) develops a hypermetabolic necrosis following status epilepticus (Nevander et al. 1985; Auer et al. 1986). We transplanted rat fetal nigral area alone or together with fetal frontal neocortex to the anterior chamber of the eye in adult rats. Following 3 months of transplant maturation the hosts were subjected to status epilepticus for 60 min. In single nigral transplants no sign of structural damage was found. In the double transplants of frontal cortex and the substantia nigra a tissue necrosis had developed in the nigral part. This was demonstrated by a total loss of glial fibrillary acidic protein (GFA) immunoreactivity within a circumscribed necrotic region in the nigral part of the double transplant. Such a loss of GFA immunofluorescence had also developed in the host SNPR, as we have earlier shown (Eriksdotter Nilsson et al. 1987). Thus, intraocular brain tissue transplants provide a unique model for studies on the development of neuronal damage and functional dependence between different neuronal structures for the development of such damage.
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  • 84
    ISSN: 1432-1106
    Keywords: Peptides ; Glial fibrillary acidic protein ; 4 vessel occlusion model of ischemia ; Immunocytochemistry ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The effects of transient (30') forebrain ischemia (4 vessel occlusion model) on peptidergic neurons and astroglial cells in various diencephalic and telencephalic areas have been analyzed. The study was performed at various time intervals of reperfusion, i.e. 4 h, 1, 7 and 40 days. Neuropeptide Y (NPY), somatostatin (SRIF), cholecystokinin (CCK), vasoactive intestinal polypeptide (VIP) and arginin-vasopressin (AVP) immunoreactive (IR) neuronal systems and glial fibrillary acidic protein (GFAP)-IR glial cells have been visualized by means of the indirect immunoperoxidase procedure using the avidin-biotin technique. The analysis was performed by means of computer assisted microdensitometry and manual cell counting. At the hippocampal level a huge reduction of neuropeptide (CCK, SRIF, VIP) IR cell bodies was observed, still present 40 days after reperfusion. On the contrary, in the frontoparietal cortex the number of the neuropeptide (CCK, SRIF, VIP, NPY) IR neurons showed a decrease at 4 h, 1 and 7 days after reperfusion followed by a complete recovery at 40 days. A rapid reduction followed by an almost complete recovery (7 days after reperfusion) was also observed at striatal level where SRIF- and NPY-IR neurons were detected. A marked decrease of NPY-IR terminals was observed in the paraventricular and periventricular hypothalamic nuclei and in the paraventricular thalamic nucleus. AVP-IR was markedly reduced in the magnocellular part of the paraventricular nucleus throughout the analyzed period (7 days after reperfusion). GFAP-IR was increased in the hippocampal formation and neostriatum while a not consistent increase was observed at neocortical level. These data point to a differential recovery of peptide-IR and to a different astroglial response in the various brain areas after transient forebrain ischemia. Region-specific factors rather than factors related to neuronal chemical coding seems to play a major role in determining the vulnerability of neuronal populations to transient ischemia.
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  • 85
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    Experimental brain research 81 (1990), S. 161-166 
    ISSN: 1432-1106
    Keywords: AChE-positive neurons ; Hippocampus ; Pharmacohistochemistry ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Acetylcholinesterase (AChE)-positive neurons were counted in the different layers of the rostral (septal) third, the middle third and the caudal (temporal) third of the hippocampus from 3 month (young) and 27 month old rats (aged) using AChE stained cryostat sections. The rats were treated with 3 and 2.5 mg of diisopropylphosphofluoridate/kg body weight, respectively 3 h before sacrifice. The study showed — 1) a high numerical density of AChE-positive neurons (10.9 to 18.9 perikarya/mm2) in the hilus (fascia dentata), the str. oriens/pyramidale of CA1 and the subiculum, a particularly low density (〈 0.1 perikarya/mm2) in the str. granulosum and moleculare of the dentate area; — 2) a significant (p 〈 0.05) linear increase of the numerical density in most of the hippocampal layers from the rostral to the caudal pole; — 3) no significant differences between young and aged animals; — and 4) a higher sensitivity to DFP-treatment in aged than in young animals. The distribution of AChE-positive neurons corresponds with the distribution of somatostatin-immunoreactive neurons described in the literature. A modulatory effect on neurotransmission is discussed as a possible function of the AChE in peptidergic neurons.
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  • 86
    ISSN: 1432-1106
    Keywords: Axonal transport ; Opioid receptor ; Axonal receptors ; Vagal receptors ; Spinal nerve receptors ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary We have utilized the technique of in vitro autoradiography to ascertain that opioid receptors are transported in the rat vagus nerve and in the rat dorsal spinal root fibers. In the dorsal roots, opioid receptors accumulated on both sides of the ligatures. In the vagus nerve, a distal accumulation of binding sites was difficult to detect, however, proximal to the ligatures, vagal receptors accumulated in a linear fashion during the first 12 h of ligation. At longer periods after ligation, accumulation was less than expected and the receptors appeared to migrate retrogradely. The receptor transport could be blocked by intravagal colchicine injection and the receptor translocation could be elicited in isolated vagal nerve segments suggesting that the receptors move by fast transport. Sodium chloride, present in the incubation medium, inhibited [3H]dihydromorphine ([3H]DHM) binding to receptors adjacent to and far from the proximal aspect of the ligature with IC50's of 42 mM and 51 mM, respectively. The addition of GTP in the incubation medium also inhibited [3H]DHM binding to “proximal’ and “far proximal” receptors with IC50's of 0.27 μM and 1.0 μM, respectively. The presence of GTP also inhibited [3H]naloxone ([3H]Nal) binding to “proximal” and “far proximal” receptors with IC50's of 0.34 μM and 0.66 μM, respectively. The transported vagal opioid receptors bound the ligands in a stereospecific manner. Using [3H]DHM, [3H]D-ala2-D-leu5-enkephalin ([3H]DADL), and [3H]ethylketocyclazocine ([3H]EKC), we found that most of the transported vagal receptors have mupharmacology although kappa and delta receptors are present.
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  • 87
    ISSN: 1432-1106
    Keywords: Hippocampus ; CA3 pyramidal cells ; Antiepileptic agent ; Calcium channel blocker ; Verapamil ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary We studied the effects of the organic calcium channel blocker, verapamil, on spontaneous and bicuculline-induced epileptiform burst discharges in CA3 pyramidal cells of hippocampal slices. A transient increase of burst discharge rate was observed in most cells within 30 min after the addition of verapamil (100 μM) to the perfusing medium. Prolonged verapamil perfusions gradually reduced the rate and duration of burst discharges, then abolished them in all tested slices (over periods of 50–150 min) without blocking synaptic transmission. Responses to intracellular injections of current pulses were also gradually affected by verapamil: Action potential amplitude was decreased, action potential duration increased, frequency adaptation increased, amplitude of the fast hyperpolarization following a single action potential decreased, and amplitude and duration of the slow afterhyperpolarization markedly reduced. The amplitude of calcium spikes elicited in slices perfused with tetrodotoxin-containing medium was not affected by verapamil, but the mean velocity of depolarization near the peak of the calcium spike was decreased. Membrane resting potential and input resistance were not affected by verapamil. These results confirm that verapamil is able to suppress epileptiform activity, but suggest that this effect is rather non-specific, due to inhibition of both postsynaptic sodium and calcium conductances.
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  • 88
    ISSN: 1432-1106
    Keywords: Neuropeptide Y ; Dopaminergic mesencephalic pathway ; Nucleus accumbens ; Immunohistochemistry ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The density of neuropeptide Y (NPY) immunostained neurons examined in the rat nucleus accumbens (NAcc) was shown to be constant across the anteroposterior extent of the nucleus and did not present any right-left hemispheric difference. Selective unilateral 6-hydroxydopamine (6-OHDA) lesion of the nigral dopaminergic neurons induced, 15 to 21 days later, a bilateral decrease in the NPY neuron density which was, interestingly, more marked in the contralateral than in the ipsilateral NAcc. Dopamine depletion induced by α-methylparatyrosine treatment elicited a decrease in NPY neuronal density similar in amplitude to that induced by the 6-OHDA lesion in the ipsilateral NAcc suggesting that similar mechanisms underly both NPY responses. In both experimental conditions, changes in NPY immunostaining were quite homogeneous in the two antero-posterior NAcc portions arbitrarily considered. Apomorphine treatment in animals with 6-OHDA injury completely reversed the ipsilateral lesion effect in the anterior part of the NAcc but only partially the contralateral one. In contrast, no significant effect of apomorphine was observed in either side of the NAcc posterior portion. This data suggests the involvement of at least 2 components in the NPY neuron responses to the lesion. The component reversed by apomorphine treatment was presumed to be directly linked to the DA depletion, while the second component not antagonized by apomorphine was considered independant on DA transmission. These data therefore provide morphological evidence for the occurence of complex functional interactions between dopaminergic afferents and NPY-containing neurons within the NAcc.
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  • 89
    ISSN: 1432-1106
    Keywords: Parvalbumin ; GABA ; Nonpyramidal cell ; Monoclonal antibody ; Lectin ; Proteoglycan ; Cerebral cortex ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Monoclonal antibody HNK-1 is shown to outline selectively a subpopulation of GABAergic neurons containing a specific calcium-binding protein parvalbumin (PV) in the adult rat parietal cortex, using preand postembedding immunocytochemistry at light microscopic level. About 98% of HNK-1 stained cells in the rat parietal cortex were PV immunoreactive. About 95% of HNK-1 immunoreactive cells were also shown to be stained with a lectin, Vicia villosa agglutinin (VVA), with a specific affinity for terminal N-acetylgalactosamine, which has been previously shown to stain selectively a subpopulation of PV-containing GABAergic neurons in this region. Furthermore almost all HNK-1 immunoreactive cells were also stained with a monoclonal antibody, 3B3, which is specific for chondroitin sulfate proteoglycan. 3B3 was shown in the present study to stain selectively a subpopulation of PV-immunoreactive neurons in the adult rat parietal cortex. In addition, a direct comparison of two monoclonal antibodies HNK-1 and VC1.1 revealed that these two were identical in their staining properties and that they defined the same subset of PV-containing GABAergic neurons in the rat parietal cortex.
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  • 90
    ISSN: 1432-1106
    Keywords: Neonatal grafts ; Nigral transplant ; Dopamine ; Aphagia ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Previous studies have shown that dopamine-rich nigral grafts, implanted bilaterally into the intact neonatal brain, will provide some protection from the eating disorders induced by subsequent nigrostriatal 6-OHDA lesions. This has been repeated in the present study using unilaterally transplanted nigral grafts. Following adult lesions, the control animals displayed the full syndrome of aphagia, adipsia and akinesia. By contrast, 37% of the rats in the transplanted group recommenced eating following the adult lesion. Recovery was related to the size and position of the graft: protection was associated in particular with transplants located in the posterior-ventral neostriatum. The results are discussed in terms of specific patterns of graft-host interaction that may underlie protection of the regulation of eating from the loss of forebrain dopamine systems.
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  • 91
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    Experimental brain research 80 (1990), S. 196-200 
    ISSN: 1432-1106
    Keywords: Long-term depression ; Longterm potentiation ; Hippocampus ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary In slices of rat hippocampus, a train of conditioning pulses that would produce long-term potentiation (LTP) if applied to afferent inputs was found to produce a long-lasting depression of Schaffer collateral/ commissural synapses on CA1 cells when instead it was applied to the CA1 axons. The depression lasted undiminished for up to 2 h (the maximum duration of recording). Intracellular recording showed that long-term depression (LTD) of e.p.s.p. amplitude occurred in 66% of cells when this antidromic conditioning stimulation was delivered in normal medium, and in 100% of cells when the antidromic stimulation was delivered in medium containing sufficient Mg++ to block all synaptic transmission. We infer that the difference is because conditioning stimuli sometimes activated test synapses in normal Mg++ but could not in high Mg++. The fact that LTD could be induced in high Mg++ eliminates enhanced inhibitory feedback as a possible mechanism of the long lasting synaptic depression and demonstrates that the mechanism is probably postsynaptic. Resting membrane potential and cell input resistance were the same before and after conditioning, so persisting changes in these postsynaptic parameters can not be the explanation for LTD. LTD of the sort described in this paper could have significant implications for models of learning and memory.
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  • 92
    ISSN: 1432-1106
    Keywords: Tuberomammillary nucleus ; Histaminergic system ; E groups ; Efferent projection ; Medial preoptic area ; Inferior colliculus ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The efferent projections of the five histaminergic neuronal subgroups in the tuberomammillary nucleus to the medial preoptic area (MPO) and inferior colliculus (IC) were examined by immunocytochemistry with antihistidine decarboxylase (HDC) antibodies combined with retrograde axonal tracing with Fast Blue (FB). The term “E groups” were used for the histaminergic neuronal subgroups. About 10% of the HDC-immunoreactive (HDCI) neurons were retrogradely labeled after FB injection into the MPO. The labeled neurons were not concentrated in any particular area, but were diffusely distributed bilaterally in all the subgroups. About two-thirds of the labeled neurons were observed on the side ipsilateral to the injection site and one-third on the contralateral side. The percentages of labeled neurons (double-labeled neurons/HDCI neurons) in the five subgroups were not significantly different with each other. The percentages in group E1 and E2 were particularly close, while that in group E4 resembled that in group E5. About 4% of the HDCI neurons were retrogradely labeled after the dye injections into the IC, and about half of the labeled neurons were detected on the ipsilateral side. The percentage of the double-labeled neurons in the five groups were not significantly different. Furthermore, those in E1 and E2, and in E4 and E5 were almost identical, respectively, to the situation following injection of FB into the MPO. These results indicate that each subgroup of histaminergic neurons in the tuberomammillary nucleus has similar efferent projections to the MPO and IC.
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  • 93
    ISSN: 1432-1106
    Keywords: Neuropeptide ; Plasticity ; Nerve injury ; Spinal cord ; Immunohistochemistry ; Cat ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary By use of fluorescence immunohistochemistry it is shown that sciatic nerve section in cat and rat induces increased levels of immunoreactive calcitonin gene-related peptide (CGRP) in axotomized motoneurons. In the rat, this effect was clearly seen at 2–5 days postoperatively, but could not be demonstrated after 11–21 days. These findings are discussed in relation to previously proposed roles for CGRP in motoneurons.
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  • 94
    ISSN: 1432-1106
    Keywords: Bed nucleus of stria terminalis ; Central nucleus of amygdala ; Phosphoprotein ; Dopamine ; Neuropeptides ; Phosphatase inhibitor ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The distribution and morphology of neurons containing the dopamine- and cyclic AMP-regulated phosphoprotein, DARPP-32, were investigated in the bed nucleus of the stria terminalis (BST) and the central nucleus of the amygdala (CeA). DARPP-32 immunoreactive neurons are numerous in both regions, but are restricted to the lateral dorsal and the lateral juxtacapsular subdivisions of the BST, and the central lateral and lateral capsular subdivisions of the CeA. Immunoreactive neurons in the lateral dorsal BST, and the central lateral and lateral capsular CeA are similar morphologically, while those in the juxtacapsular BST appear to be a subpopulation of striatal mediumsized spiny neurons. The distribution of DARPP-32 immunoreactive neurons in the BST and CeA overlaps considerably with axonal plexuses containing tyrosine hydroxylase (TH), vasoactive intestinal polypeptide (VIP), and calcitonin gene-related peptide (CGRP). These studies provide further evidence of the close relationship between the CeA and BST, and also provide anatomical evidence for possible interactions between neurotransmitters, neuropeptides, and phosphoproteins.
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  • 95
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    Experimental brain research 79 (1990), S. 539-546 
    ISSN: 1432-1106
    Keywords: Electroretinogram ; Gratings ; Retina ; Degeneration ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The aim of this study is to investigate in the rat the properties of the pattern electroretinogram (ERG) and to assess whether it depends upon the functional integrity of ganglion cells. Flash and pattern ERG were recorded from urethane anaesthetized hooded rats. The pattern ERG was evoked by phase alternating gratings of various spatial frequencies and contrasts. In the first part of the study we determined how the amplitude of the main harmonic of the pattern ERG (2nd harmonic) varies as a function of stimulus parameters such as spatial and temporal frequency, contrast and mean luminance. In the second part of the study we investigated the effects of the retrograde degeneration of ganglion cells following optic nerve section on the amplitude of pattern ERG. We found that the section of the optic nerve leads to the progressive disapperance of the P-ERG which is almost complete 4 months after surgery. By this time only few axotomized ganglion cells are left. The flash ERG remained unaffected. Thus, the pattern electroretinogram seems to be a simple and sensitive tool to investigate the functional integrity of retinal ganglion cells in rats.
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  • 96
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    Experimental brain research 80 (1990), S. 49-53 
    ISSN: 1432-1106
    Keywords: Hierarchical processing ; Sensory cortex ; Reciprocal connections ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The prevalence of reciprocal connections in the cerebral cortex indicates that they play a fundamental role in the processing of sensory information. We have investigated the laminar termination patterns of such paired connections between different visual cortical areas of the rat, and have found two basic projection types: one which includes layer 4 and a second which includes layer 1 and avoids layer 4. The projections from primary visual cortex (area 17) to extrastriate visual cortical targets in the cytoarchitectonical areas 18a and 18b, and from 18a to a site in 18b, are of the first type. In contrast, the return projections from 18a and 18b to area 17 and from 18b to 18a, are of the second type. Thus each pair of connections has one element of each type, giving every circuit a nearly identical asymmetric structure. These laminar patterns resemble those of forward and feedback connections in primate cortex, indicating that cortico-cortical connectivity patterns are highly conserved through evolution, and that, as in monkeys, these connections define a hierarchical organization of areas in rat visual cortex.
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  • 97
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    Experimental brain research 81 (1990), S. 53-58 
    ISSN: 1432-1106
    Keywords: Vasopressin ; Oxytocin ; Adrenocorticotrophic hormone ; Emotional stress ; Opioid ; Prolactin ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The effects of an opioid receptor antagonist, naloxone (NAL), were studied on the changes in pituitary hormone secretion induced by emotional stress. Male Wistar rats were trained with tone stimuli paired with electric footshocks and tested with the tone and environmental cue signals for emotional stress of fear acquired by learning as described previously (Onaka et al. 1988). Rats received s.c. injected NAL 30 min before testing at doses of 0, 0.2, 1.0, 5.0 and 25.0 mg/kg b.w. Half the rats were injected with 0.5 M NaCl (20 ml/kg b.w.) together with NAL. In these hypertonic rats plasma vasopressin level was slightly increased after NAL. The increment was statistically significant in control groups but not in experimental groups. However the suppression of vasopressin secretion by emotional stimuli was not changed by NAL. Plasma oxytocin levels were extremely high and not significantly different among experimental, unshocked control and untested control groups. NAL further increased the oxytocin level dose-dependently. NAL did not significantly change plasma adrenocorticotrophic hormone (ACTH) levels and hence did not modify the augmentative response in ACTH secretion to emotional stimuli. Plasma prolactin level was significantly elevated after emotional stimuli and NAL depressed the prolactin level in each of experimental and control groups. After NAL, the magnitude of the facilitatory response in prolactin secretion to emotional stimuli was decreased. Motor activity and its suppressive response to emotional stimuli were not influenced by NAL. In another half of rats under a normal osmotic condition the vasopressin response to emotional stimuli was not affected by NAL. NAL further augmented potentiation of oxytocin secretion after emotional stimuli dose-dependently. Effects of NAL on ACTH level, prolactin level and motor activity were similar to those in rats under hypertonic conditions. These results demonstrate that endogenous opioids are selectively and differentially involved in hypothalamo-hypophysial responses to fear-related emotional stress.
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  • 98
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    Experimental brain research 83 (1990), S. 225-227 
    ISSN: 1432-1106
    Keywords: Substantia gelatinosa ; Dendrites ; Neuronal development ; Spinal cord ; Golgi technique ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Two types of neurons were observed in the substantia gelatinosa (SG) of the rat spinal cord which exhibit wide variations in dendritic symmetry. As demonstrated with the Golgi technique, “islet” cells with short dendritic arbors and “type III stalk” cells display dendritic patterns which vary from a bipolar type arrangement with two dendritic arbors of nearly equal dimensions to a unipolar arrangement with a dendritic arbor which extends in only one direction. Examination of the morphology and dendritic development of these neurons shows that they are unique compared with other SG neurons in that they have short, longitudinal dendritic arbors which undergo maturation relatively late in the postnatal period. As is discussed, variations in dendritic symmetry are probably dependent on the location of the terminal fields of primary and/or other types of afferents which are formed earlier in development.
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  • 99
    ISSN: 1432-1106
    Keywords: Ischemia ; Hippocampus ; Neocortex ; Striatum ; Calbindin ; Parvalbumin ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The relationship between neuronal calcium binding protein content (calbindin D28K: CaBP and parvalbumin : PV) and vulnerability to ischemia was studied in different regions of the rat brain using the four vessel occlusion model of complete forebrain ischemia. The areas studied, i.e. the hippocampal formation, neocortex, neostriatum and reticular thalamic nucleus (RTN), show a characteristic pattern of CaBP and PV distribution, and are involved in ischemic damage to different degrees. In the hippocampal formation CaBP is present in dentate granule cells and in a subpopulation of the CA1 pyramidal cells, the latter being the most and the former the least vulnerable to ischemia. Non-pyramidal cells containing CaBP in these regions survive ischemia, whereas PV-containing non-pyramidal cells in the CA1 region are occasionally lost. Hilar somatostatin-containing cells and CA3 pyramidal cells contain neither PV nor CaBP. Nevertheless, the latter are resistant to ischemia and the former is the first population of cells that undergoes degeneration. Supragranular pyramidal neurons containing CaBP are the most vulnerable cell group in the sensory neocortex. In the RTN the degenerating neurons contain both PV and CaBP. In the neostriatum, ischemic damage involves both CaBP-positive and negative medium spiny neurons, although the degeneration always starts in the dorsolateral neostriatum containing relatively few CaBP-positive cells. The giant cholinergic interneurons of the striatum contain neither CaBP nor PV, and they are the most resistant cell type in this area. These examples suggest the lack of a consistent and systematic relationship between neuronal CaBP or PV content and ischemic vulnerability. It appears that some populations of cells containing CaBP or PV are more predisposed to ischemic cell death than neurons lacking these proteins. These neurons may express high levels of calcium binding proteins because their normal activity may involve a high rate of calcium uptake and/or intraneuronal release.
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  • 100
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    Experimental brain research 80 (1990), S. 148-156 
    ISSN: 1432-1106
    Keywords: Superior colliculus ; Blood pressure ; Heart rate ; N-methyl D-aspartate ; Defence ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Electrical stimulation and microinjections of the GABA antagonist bicuculline methiodide into the superior colliculus (SC) of the anaesthetized rat can evoke changes in blood pressure and heart rate. The long latency of bicuculline evoked responses, however, raises the possibility that they may have been produced by the diffusion of bicuculline to surrounding tissue, in particular, the periaqueductal gray. Thus, the purpose of the present study was to investigate whether such changes could have been produced by the activation of extracollicular neural elements. This was achieved by assessing the relative regional sensitivity of the SC and underlying structures (periaqueductal gray and dorsal tegmentum) with microinjections of the excitatory amino acid N-methyl D-aspartate (NMDA) for the production of short latency pressor responses. Dorsal midbrain injections of NMDA (200 nl of 100 mM) in the Saffan anaesthetized rat evoked clear short latency (single or double phase) increases in blood pressure accompanied in most cases by a longer latency increase in heart rate and respiration. Two regions within the dorsal midbrain contained significantly higher proportions of active sites compared with surrounding tissue: i) the superficial and intermediate layers of rostromedial SC, and ii) the caudal periaqueductal gray. The distribution of active sites indicated that pressor responses elicited from the rostromedial SC could not be explained by the diffusion of NMDA to underlying tissue. The question of whether the rostromedial SC might represent an early link in the circuitry responsible for organizing defensive movements and appropriate physiological changes to potentially dangerous overhead stimuli is considered.
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