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  • 1985-1989  (4,722)
  • 1980-1984  (4,542)
  • Organic Chemistry  (6,898)
  • Rat  (1,482)
  • Ultrastructure  (929)
  • Nuclear reactions
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Years
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  • 1
    ISSN: 1435-604X
    Keywords: Brain tumour ; Rat ; Detection ; Fluorescence ; Laser ; Haematoporphyrin derivative
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine , Physics , Technology
    Notes: Abstract Laser-induced fluorescence has been used for the identification of brain tumours in rats, which have been previously given tumour-seeking haematoporphyrin derivative. A pulsed nitrogen laser (λ=337 nm) was used in conjunction with an optical multichannel analyzer. For both inoculated RG-2 and TCVC rat-brain-tumour models, the blue autofluorescence was strongly reduced in the tumour compared with normal brain tissue, and at the same time the characteristic red-drug signal increased. The contrast between tumour and normal tissue was strongly enhanced by forming the ratio between the two signals. Implications for possible improvement of tumour delineation in brain tumour surgery are discussed.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Naunyn-Schmiedeberg's archives of pharmacology 339 (1989), S. 178-183 
    ISSN: 1432-1912
    Keywords: Rat ; Urinary bladder ; Somatovesical inhibitory response ; Colovesical inhibitory response ; Capsaicin sensitive afferents
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary (1) The effect of perineal pinching and distension of a balloon inserted into the colon on motility of the urinary bladder has been investigated in adult urethane-anesthetized rats pretreated with capsaicin (50 mg/kg s.c.) or its vehicle 4 days before the experiments. (2) At bladder volumes which were sufficient to elicit reflex micturition, perineal pinching or colonic distension transiently inhibited the ongoing bladder voiding contraction. The somato-vesical inhibitory response was markedly reduced or even abolished by division of pudendal nerves. Neither the somato-vesical nor the colovesical inhibitory response were modified by desensitization with systemically administered capsaicin. (3) Intraurethral administration of capsaicin produced a transient inhibition of the reflexly-activated bladder contractions. A second administration of the drug was less effective, indicating desensitization. Intravenously administered capsaicin had a similar inhibitory effect on bladder motility. (4) The vesico-inhibitory response produced by intraurethral administration of capsaicin was not affected by phentolamine, propranolol, guanethidine, picrotoxin or naloxone, while it was greatly reduced or even abolished by bilateral section of the pudendal nerves. (5) These findings provide evidence that capsaicin-sensitive chemoreceptors in the rat urethra are involved in generating a vesico-inhibitory response via pudendal nerves. On the other hand, no evidence was found for the participation of capsaicin-sensitive nerves in the generation of the somato- or colo-vesical inhibitory response.
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  • 3
    ISSN: 1432-1912
    Keywords: Rat ; Forebrain ischemia ; Local cerebral blood flow ; Neuronal damage ; Emopamil
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The effects of the calcium entry blocker emopamil on physiological variables, local cerebral blood flow (LCBF) and on hippocampal cell damage were evaluated after 10 min of forebrain ischemia in the rat. LCBF was determined with the 14C-iodoantipyrine technique after 2, 10, and 60 min of postischemic recirculation. Histological evaluation was performed 7 days after ischemia in cortical and hippocampal tissue by determination of the percentage of necrotic neurons. Preischemic application of emopamil [4 mg/kg racemate or 2 mg/kg (S)-emopamil; i.v.] caused increases in LCBF in cortical areas but did not alter blood flow in the hippocampus at 2 min of recirculation. After 10 and 30 min of flow resumption no differences in LCBF between drug-treated and control animals were observed. In the histological series (S)-emopamil was applied at doses of 2, 4 or 6 mg/kg before the induction of ischemia. After 7 days of postischemic recovery, neuronal damage was significantly reduced by the calcium antagonist in hippocampal CA 1 sector at all doses tested, the most prominent effects being observed with the lowest dose. At this dose cell loss in the Ca3 sector was also reduced. In cortical tissue the number of necrotic cells remained unchanged by emopamil treatment. It is concluded that the calcium antagonist emopamil can reduce ischemia-induced neuronal cell damage. The compound improves circulation in cortical tissue only during early recovery but not at later phases of reflow, i.e. the period of delayed hypoperfusion. These increases in blood flow are not of crucial importance for ultimate neuronal death in this area. The ameliorative action of emopamil on the survival of hippocampal neurons is not associated with blood flow changes and therefore seems to reflect a direct effect on cerebral parenchyma.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Archives of gynecology and obstetrics 244 (1989), S. 151-155 
    ISSN: 1432-0711
    Keywords: Placenta ; Glycogen ; Triglyceride ; Cold ; Fasting ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The effect of exposure to cold (+2°C, 3 and 24 h) and fasting (1, 2 and 3 days) on placental glycogen and triglyceride content was investigated in rats pregnant for 20 days. The stimuli did not affect the level of glycogen in the placenta. The level of triglycerides remained unchanged in the rats exposed to cold. It rose after only one day of fasting and then levelled out on the 2nd and 3rd days. Fasting, but not exposure to cold produced hypoglycemia and elevation of the plasma free fatty acids level. We conclude that activation of the adrenergic system during exposure to cold does not interfere with the glycogen and triglyceride content of the placenta. Prolonged hypoglycemia also does not affect the placental glycogen level although it increases the accumulation of neutral fat.
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  • 5
    ISSN: 1432-1432
    Keywords: Carcinoembryonic antigen ; Evolution ; Gene family ; Human ; Rat ; Synonymous substitutions ; Silent molecular clock ; Evolutionary trees
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Various rodent and primate DNAs exhibit a stronger intra- than interspecies cross-hybridization with probes derived from the N-terminal domain exons of human and rat carcinoembryonic antigen (CEA)-like genes. Southern analyses also reveal that the human and rat CEA gene families are of similar complexity. We counted at least 10 different genes per human haploid genome. In the rat, approximately seven to nine different N-terminal domain exons that presumably represent different genes appear to be present. We were able to assign the corresponding genomic restriction endonuclease fragments to already isolated CEA gene family members of both human and rat. Highly similar subgroups, as found within the human CEA gene family, seem to be absent from the rat genome. Hybridization with an intron probe from the human nonspecific cross-reacting antigen (NCA) gene and analysis of DNA sequence data indicate the conservation of noncoding regions among CEA-like genes within primates, implicating that whole gene units may have been duplicated. With the help of a computer program and by calculating the rate of synonymous substitutions, evolutionary trees have been derived. From this, we propose that an independent parallel evolution, leading to different CEA gene families, must have taken place in, at least, the primate and rodent orders.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Virchows Archiv 414 (1989), S. 113-119 
    ISSN: 1432-2307
    Keywords: Gastric mucosa ; Intestinal metaplasia ; Ciliated cell ; Ciliated metaplasia ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Intestinal metaplasia of the gastric mucosa occurs commonly in aged Japanese patients and has been discussed in relation to the high incidence of gastric cancer in Japanese. Ciliated cells in the gastric mucosa have frequently been found in association with intestinal metaplasia in the pyloric gland and rarely in the cardiac gland in many Japanese patients, and exceptionally in one Chinese and in one Swedish patient. Electron microscopic examination of 12 Japanese patients has revealed that these structures are not metaplastic stereocilia, but true cilia. Ciliated cells have been found in the basal part of the gastric glands and never in the surface epithelium. The fine structure of the gastric cilia was almost the same as that of normal respiratory cilia. However, in the gastric cilia, most dynein arms were inconspicuous even after tannic acid fixation, indicating that ciliary beating of the gastric cilia is problematic. Abnormal cilia and basal bodies also were found. Ciliated cells have always occurred in association with intestinal metaplasia, therefore this phenomenon might be a type of metaplasia and is named “ciliated metaplasia” of the gastric mucosa.
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  • 7
    ISSN: 1432-2307
    Keywords: Hyperoxia ; Lung broncho-vascular reaction ; Electron microscopy ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary In order to clarify the early phenomena involved in the lung reaction to hyperoxia, twenty adult male rats were exposed to 100% oxygen at 1 ATA. Morphological pulmonary lesions were detectable after only 24 h hyperoxia, and included vasoconstriction and perivascular oedema, bronchiolar constriction, and pericyte reaction. The lesions were irregularly scattered within the lung parenchyma and occurred preferentially in areas centred on bronchiolo-vascular stems. Even at the latest stages, pulmonary heterogeneity was obvious, from the coexistence of areas damaged at different times. Neuro-epithelial-bodies were found under the bronchiolar epithelium; the morphological aspect of the neuro-endocrine cells observed was consistent with hyperoxia-induced modulation of their secretory activity. Taken together, our findings show the speed of development of hyperoxia-induced pulmonary changes and raise some pathogenic considerations.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Springer
    Virchows Archiv 414 (1989), S. 459-464 
    ISSN: 1432-2307
    Keywords: Sebaceous carcinoma ; Parotid gland ; Salivary gland ; Ultrastructure ; Immunohistochemistry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Sebaceous carcinoma of salivary gland origin is extremely rare and, because of its rarity, the clinicopathological characteristics and the histogenesis are not fully understood. We present a case of sebaceous carcinoma of the parotid gland which brings the total number of reported cases to 22. The tumor showed epithelial cell nests which were mainly composed of sebaceous cells with marked cellular atypia. In most of the nests, glandular spaces lined by ductal epithelium were present. Scattered mucous cells and flattened eosinophilic cells at the periphery of the nests were also seen. Ultrastructural and immunohistochemical observations of the tumour revealed coexistence of sebaceous and glandular differentiations in some tumour cells. Tumour cells with lipid granules often participated in the formation of glandular structures or exhibited intracytoplasmic lumina, and immunohistochemical localization of lactoferrin and secretory component, the functional markers of ductal epithelium of salivary gland, was demonstrated not only in duct-forming tumour cells but also in many sebaceous tumour cells. It seems likely that sebaceous carcinoma originates from pluripotential duct cells which can differentiate into sebaceous, ductal and mucous cells.
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  • 9
    Electronic Resource
    Electronic Resource
    Springer
    Virchows Archiv 415 (1989), S. 145-149 
    ISSN: 1432-2307
    Keywords: Paracrystalline inclusion ; Microtubule ; Ciliogenesis ; Gastric ciliated cell ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Unusual electron-dense paracrystalline inclusions were found in metaplastic ciliated cells in the stomachs of three Japanese male patients with gastric carcinoma. These patients had not been given antitumour drugs before surgery and ethrane (enflurane) was used as the anaesthetic. Ciliated cells in the gastric mucosa are found not infrequently in the pyloric glands in association with intestinal metaplasia in elderly Japanese patients. Paracrystalline inclusions were found only in the ciliated cells and never in any other types of gastric mucosal cell. These inclusions were located in the apical portion of the ciliated cells in intimate association with the basal bodies. They consisted of twisted strings about 27 nm wide with a regularly repeated spacing of about 30 nm. On highly magnified electron micrographs, granules about 4 nm in diameter were detected. These paracrystalline inclusions have never been reported previously, although their location in ciliated cells and their morphological characteristics suggest an intimate relationship with the ciliogenesis of metaplastic ciliated cells in the human stomach.
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  • 10
    ISSN: 1432-2307
    Keywords: Malignant fibrous histiocytoma ; Ultrastructure ; Enzyme histochemistry ; Immunohistochemistry ; “Fibrohistiocytoid cell”
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Ultrastructural, enzyme histochemical and immunohistochemical studies were performed on tissue obtained from eight cases of malignant fibrous histiocytoma (MFH) and five cases of sacral decubitus ulcer. The MFH was composed of two major tumour cell types: fibroblast-like and histiocyte-like cells. Both cell types demonstrated abundant branching, fragmented rough endoplasmic reticulum (rER), many free ribosomes, occasional small mitochondria, an oval, elliptical or irregularly shaped nucleus with one or two prominent nucleoli and often a few dense bodies. However, pseudopodial projections, multivesicular bodies and phagosomes, common histiocyte organelles, were not seen. With little difference between cases or selection sites, the MFH cells reacted to acid phosphatase (AcP) and α-naphtyl butyrate esterase (ANBE) by enzyme histochemistry and with ferritin (Fer), α1-antitrypsin (AT), α1-antichymotrypsin (ACT), fibronectin (FN), HLA-DR, HLA-DP, Leu 10 and OKT 9 in immunohistochemical studies. MFH tumour cells did not immunostain with monocyte/macrophage markers (Leu M1, Leu M3, Mo 1, Mo 2 and Macrophage) although non-neoplastic histiocytes did react to these markers. In addition, granulation tissue, such as that found in sacral decubitus ulcers, was examined and the existence of a specific cell type called the “fibrohistiocytoid (FH) cell” was documented. The FH cell was short, spindle shaped and elliptical. Ultrastructurally, it had fragmented rER distributed in a branching pattern, dispersed free ribosomes, small mitochondria and a few dense bodies, but lacked diverse fused lysosomes and distinct pseudopodial cytoplasmic extensions. The FH cells reacted with AcP, alkaline phosphatase and ANBE but not with peroxidase using enzyme histochemistry and with Fer, AT, ACT, FN, HLA-DR, HLA-DP, Leu 10 and OKT 9 but not with monocyte/macrophage markers, C3d receptor, C3bi receptor in immunohistochemical studies. The FH cells had morphological, enzyme histochemical and immunohistochemical characteristics intermediate between fibroblasts and histiocytes. Similarities between MFH cells and the FH cells seen in chronic inflammation are discussed.
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  • 11
    Electronic Resource
    Electronic Resource
    Springer
    Virchows Archiv 415 (1989), S. 21-29 
    ISSN: 1432-2307
    Keywords: Alcoholic liver disease ; Ultrastructure ; Phagocytosis ; Cell shedding
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Sinusoidal macrophages were studied by light and electron microscopy in 49 liver biopsies from alcohol-abusers with a variety of alcohol-related liver lesions or with near-normal livers. Changes were related to those in nearby hepatocytes. A reduction in the number of macrophages was noted in the more severely damaged livers. Hepatocytes formed blebs at their sinusoidal poles, and these protruded into the space of Disse and into the sinusoidal lumen. It is postulated that reduced phagocytic activity in the livers of patients with severe alcohol-related liver disease leads to increased shedding of hepatocellular material into the circulation. This may promote the development of autoimmune reactions directed against hepatocytes.
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  • 12
    ISSN: 1432-2307
    Keywords: Keratin ; Mammary neoplasms ; Mouse ; Rat ; Immunohistochemistry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Using immunoperoxidase staining of monoclonal antibody 312C8-1 against 51 000 dalton human keratin polypeptide, immunolocalization was observed in frozen sections of normal tissue and mammary tumours of adult female mice and rats. In normal tissue, the epitope was recognized in myoepithelial cells of the mammary, sweat and salivary glands, and in basal and suprabasal cells of the epidermis. However, the antibody did not react with luminal epithelial cells of the above glands or with mesenchymal cells. In spontaneous mammary tumours of mice, marker-positive tumour cells were distributed only in the outer layer of adenocarcinoma Type A, while they were scattered in some foci of adenocarcinoma Type B, and encircled the epithelial foci of pregnancy dependent tumours (plaque). All layers of epidermoid structures in adenoacanthoma revealed positivity. In rat mammary tumours induced by local dusting with 7, 12-dimethylbenz(α)anthracene (DMBA) powder, the staining pattern of benign tumours was comparable to that of the normal mammary gland. But, in addition to basally situated cells, marker-positive tumour cells were found scattered in the foci of adenocarcinoma, and were not restricted to basal cells in squamous cell carcinoma. The marker was not found in sarcomatous tissue. This antibody can therefore also be applied to rodents, and the staining pattern can be used to identify the epithelial subclass specific marker in normal tissue and in mammary tumours.
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  • 13
    Electronic Resource
    Electronic Resource
    Springer
    Research in experimental medicine 189 (1989), S. 281-287 
    ISSN: 1433-8580
    Keywords: Serotonin ; Tryptophan ; Small intestine ; Rat ; Pargyline
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary To investigate the release of serotonin from intestinal enterochromaffin cells, we used an in vitro technique which allows studies excluding overlapping influences from outside the gut. The entire small intestine of rats fed a standard or tryptophan-enriched (3% of total) diet was totally isolated by ligatures with the exception of the superior mesentric artery and portal vein that supply and drain the intestine. Simultaneously to the vascular perfusion (Krebs-Ringer bicarbonate buffer, 0,4% human albumin, 5 mM glucose, 0.6 mM glutamine) the gut lumen was infused (buffer or 0.1 N HCL). Acidification of the gut lumen resulted in an increment of venously released tryptophan and serotonin. After feeding tryptophan-enriched food the release of tryptophan was increased. However, the total amount of released serotonin after tryptophan diet did not differ as compared to that after standard diet. Addition of a monoamino-oxidase inhibitor (pargyline) to the arterial perfusate enhanced the released amount of serotonin 3-fold in the portal venous effluent (at a concentration of 1 mM but not 0.1 mM). Recovery studies done by arterial infusions of serotonin (1 µM, 10µM) and evaluation of the amounts venously released revealed a high loss of infused serotonin (40%–70%). Our data suggest gut-born serotonin to more likely play a paracrine role than a role as a classical hormone.
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  • 14
    ISSN: 1433-8580
    Keywords: Rat ; Liver cirrhosis ; Hypoxia ; Redox state ; Mitochondrial oxidative phosphorylative activity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The influence of hypoxia on hepatic mitochondrial function and energy status was studied in normal and carbon tetrachloride (CCl4)-induced cirrhotic rats. Under hypoxemia of 50 mm Hg-PaO2, hepatic energy status was suppressed both in normal and cirrhotic rats. After the reversal of hypoxia, it was completely restored in normal rats concomitant with a rapid elevation of hepatic mitochondrial redox state (overshoot phenomenon) and increase in the mitochondrial oxidative phosphorylative activity. By contrast, in cirrhotic rats, such an enhancement of mitochondrial function was not observed. It was clarified that cirrhotic liver mitochondria have little capacity to respond to the hypoxic stress. A lower resistance to hypoxic episode in cirrhotics might be attributable to the absence of mitochondrial enhancement which is a compensatory mechanism for the deranged energy metabolism of the liver.
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  • 15
    Electronic Resource
    Electronic Resource
    Springer
    Research in experimental medicine 189 (1989), S. 321-329 
    ISSN: 1433-8580
    Keywords: Fibronectin ; Nerve fibrosis ; Fibrin adhesives ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Although the fibrin adhesion enjoys increasing success in many areas of surgery, it has not, however, become fully established in nerve anastomosis. It was in this area particularly that significant advantages were expected, especially by the avoidance of suture granulomas. As the fibrin clot dissolved prematurely, however, and dehiscences ensued, antifibrinolytic substances had to be added to the adhesive. Fibroses occurred frequently as a result, which to date encumber nerve adhesive. We examined fibronectin for its fibrosis-inducing effect, comparing both presently available fibrin adhesive systems, because one contained up to 5 times more fibronectin per milliliter than the other. On the basis of a test grouping using 100 and 1000 KIU aprotinin/ml, we were able to establish that fibronectin in fibrin adhesives possesses a fibrosis-promoting effect.
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  • 16
    Electronic Resource
    Electronic Resource
    Springer
    Acta neuropathologica 78 (1989), S. 264-269 
    ISSN: 1432-0533
    Keywords: Skeletal muscle ; Regeneration ; Growth factors ; Growth hormone ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Against the background of the importance of growth hormone (GH) for normal muscle growth, a study was performed to investigate whether lack of GH after hypophysectomy affects the cell proliferation and the local production of insulin-like growth factor-I (IGF-I) in the early stages of muscle regeneration in adult rats. The level of IGF-I in the serum of hypophysectomised rats was reduced to about 30% of that of controls. The incorporation of [methyl-3H]thymidine into the regenerating muscle showed a peak 6 days after the operation and then gradually declined to the end of the period of study 30 days after initiation of regeneration by ischemic necrosis. The DNA content rose to a maximum level after 6–8 days, and remained high after 30 days. There was no major difference in the incorporation of [3H]thymidine in regenerating muscle of hypophysectomised and control rats, but the DNA concentration in the regenerating muscles of hypophysectomised rats was significantly reduced after 30 days. There was a corresponding reduction in the number of nuclei per muscle fibre, indicating that hypophysectomy has a small effect on the cell proliferation during the early stages of muscle regeneration. Immunohistochemical demonstration of IGF-I in the regenerating muscle revealed the transient presence of immunoreactive material in satellite cells and myotubes after 6 to 8 days of regeneration but no immunoreactivity after 30 days. No obvious difference was observed between hypophysectomised and control rats, indicating that the endogenous production of IGF-I in regenerating skeletal muscle can occur independently of GH.
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  • 17
    ISSN: 1432-0533
    Keywords: Neuronal inclusions ; Leigh disease ; Tropomyosin ; Actin ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary A novel type of non-viral cytoplasmic inclusion is described, which was seen in virtually every neuron in the brain and spinal cord of a child with a presumed metabolic disorder whose clinical picture and CNS pathology were compatible with Leigh Syndrome. The ovoid to round inclusions were sharply demarcated, measuring up to 11 μm in diameter. They showed no distinctive staining with a battery of routine histological techniques. The ultrastructural features are unique, comprising non-membrane-bounded aggregates of randomly oriented plate-like structures with parallel linear densities depicting a periodicity of 11–16 nm. Immunocytochemical studies revealed strong staining with antisera to tropomyosin and weaker staining with antisera to actin. There was no reactivity with antibodies against neurofilaments, microtubules and their associated proteins, paired helical filaments, ubiquitin, vinculin or alpha-actinin. It is postulated that the metabolic disorder resulted in a neurodegenerative condition which manifested pathologically with lesions compatible with those of Leigh Syndrome. Associated with the condition was the discrete accumulation of cytoplasmic proteinaceous components, including tropomyosin, in the form of neuronal cytoplasmic inclusions possibly resulting from an alteration of the neuronal cytoskeleton.
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  • 18
    ISSN: 1432-0533
    Keywords: Cerebral hypoxia ; Cerebral ischemia ; Ultrastructure ; Neocortex ; Brain isolation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The acute cortical response to surgical brain isolation and subsequent extracorporal normoxic or 30 min hypoxic (PaO2=20 mm Hg) perfusions (hypoxic hypoxia with relative ischemia) was evaluated. Cerebral blood flow, arterial pH and CO2 were maintained constant during both perfusions; only the arterial oxygen content was changed. The isolated brain model used in this and previous investigations produces no qualitative ultrastructural changes in the neocortex following brain isolation and normoxic perfusion. However, the acute cortical structural response to 30 min of hypoxic hypoxia with relative ischemia demonstrated a number of important observations. Hypoxic hypoxia produced ultrastructural responses common to cerebral ischemia such as nuclear chromatin clumping, nucleolar condensation and cytoskeletal breakdown. Although neuronal abnormalities seen after 30 min of hypoxic hypoxia were similar to those acute neuronal changes observed following complete cerebral ischemia without recirculation, they differed three ways: (a) mitochondrial swelling and microvacuolation were observed in many cortical pyramidal neurons. (b) Glycogen particles within astroglial processes were observed even after a 30-min period of hypoxic hypoxia. (c) Perivascular astroglial swelling was minimal despite considerable perineuronal swelling. In contrast, incomplete cerebral ischemia produces mitochondrial changes similar to those in hypoxic hypoxia but also causes the depletion of tissue glycogen and perivascular glial swelling. Thus, hypoxic hypoxia with relative ischemia produces a unique acute ultrastructural response compared to either complete or incomplete cerebral ischemia.
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  • 19
    Electronic Resource
    Electronic Resource
    Springer
    Acta neuropathologica 79 (1989), S. 168-175 
    ISSN: 1432-0533
    Keywords: Muscular ; Dystrophy ; Ovine ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The initial ultrastructural changes in skeletal myofibers in ovine muscular dystrophy (MD) consisted of focal degeneration of myofibrils and the formation of Z-disc abnormalities, including nemaline rods, in adjacent sarcomeres. Peripheral and central sarcoplasmic masses, which occurred initially in large diameter fibers, contained a mixture of normal organelles and abnormal tubular and fibrillar formations. Vesiculate sarcolemmal nuclei with prominent nucleoli accumulated in central and subsarcolemmal locations in small clusters and short rows. Deformed individual nuclei were sometimes present within nuclear rows. Loss of the myofibrillar mass, increased density of small spherical nuclei, collections of fibrillar and tubular arrays, excessive folding of the sarcolemma and greatly reduced fiber diameter were seen in the end stage of the dystrophic process. Resting satellite cells were present at all stages of lesion development. The morphological progression of the lesions suggested an inherited inability to effectively replace lost myofibrils with ultimate exhaustion of the capacity for repair followed by pathological fiber atrophy.
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  • 20
    Electronic Resource
    Electronic Resource
    Springer
    Anatomy and embryology 180 (1989), S. 175-178 
    ISSN: 1432-0568
    Keywords: Paratympanic organ ; Reciprocal synapses ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The innervation pattern of the paratympanic organ was studied by TEM. The paratympanic organ is a small tapering vesicle, typical of birds, situated in the medial wall of the tympanic cavity; it contains hair cells which are similar to type II receptors of the acoustic-lateral system; these cells are characterised by synapses which are not only afferent and efferent, as previously described, but also reciprocal with efferent fibers. Our observation revealed some efferent nerve fibers which form a relationship with hair cells containing synaptic bodies situated next to the plasma membrane and near the fibers themselves. Since synaptic bodies are commonly considered to be the site where the transmission of the impulse from the receptor to the nerve fiber takes place, our pictures suggest that the efferent fibers and hair cells may be either presynaptic or postsynaptic with respect to each other in the paratympanic organ. The hypothesis is formulated that reciprocal synapses allow interaction between hair cells, thus determining an increase in the contrast of information sent by the paratympanic organ to the CNS.
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  • 21
    ISSN: 1432-0568
    Keywords: Cecum ; Germ-free rat ; Microflora inoculation ; Morphometry ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The structural changes of the cecal wall in germfree rats were observed at regular intervals after the inoculation of fecal microflora from conventional rats. Quantitative light microscopy showed that most of the elements in the cecal wall increased at 12 or 24 h and reached peak values at 4 days after inoculation. On the 7th day, they decreased approximately to the values for conventional rats. The crypts were bent or widely open till 24 h but were not after the 4th day. Hyperplasia of the crypt epithelial cells including mucous-type cells was observed following microbial inoculation. Electron microscopy revealed that most of the epithelial cells lining the mucosa were typical columnar cells. Desquamation of the epithelial cells and contraction of the muscle fibers were often seen on 4th day. The mucous-type cells were divided into two types, goblet and non-goblet mucous-type cells. Reduction of cecal volume after microbial inoculation may be mainly caused by muscle contraction in the early period and hyperplasia and desquamation of the epithelial cells may suggest their role as the first and non-specific defense line prior to operation of the specific immune system.
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  • 22
    ISSN: 1432-0568
    Keywords: Melatonin synthesis ; Pineal gland ; Rat ; “Synaptic” ribbons ; Sympathetic stimulation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Melatonin metabolism in the mammalian pineal gland is under the clear influence of sympathetic fibers originating in the superior cervical ganglia (SCG). Previous studies suggested that pineal “synaptic” ribbons (SR) as well are regulated by the gland's sympathetic innervation. To gain more insight into the mechanisms involved, we examined the effects of sympathetic stimulation on SR number and on the activity of melatonin forming enzymes, serotonin N-acetyltransferase (NAT) and hydoxyindole-O-methyltransferase (HIOMT). The SCG in adult male rats were stimulated electrically during daytime for either 15 or 120 min. Immediately following stimulation, the glands were removed and processed for electron microscopy and for the determination of NAT and HIOMT activities. No differences in pineal SR number, size or location were found in rats stimulated with either parameters when compared with sham-stimulated or control animals. While the activity of HIOMT remained unchanged, the activity of NAT was also unaltered following 15 min of stimulation, but was augmented approximately three-fold in animals stimulated for 120 min. It is concluded that if SR in the rat pineal gland are under sympathetic control, the regulation is different from that involved in melatonin formation.
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  • 23
    ISSN: 1432-0568
    Keywords: Pyramidal tract ; Rat ; Development ; Axon loss ; Myelination
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary A quantitative electron microscopic analysis was undertaken of the development of the pyramidal tract, at the level of the third cervical spinal segment, in rats ranging in age from the day of birth to three months old. The axon number was calculated as the product of axon density, determined in a systematic random sample of electron micrographs, and tract area. During the first postnatal week the tract contains thin unmyelinated axons and growth cones. Growth cones are abundant in neonatal rats, but can still be observed occasionally at the end of the first postnatal week, indicating a continuous addition of pyramidal tract axons during the first postnatal week. Myelination starts around P10. By the end of the first postnatal month approximately 50% of the axons have already been myelinated. Myelination proceeds during further maturation, but in the three month old rat 28% of the axons are still unmyelinated. The total number of axons increases rapidly after birth up to 153 000 at the fourth postnatal day. Subsequently, the number of axons is reduced by nearly 50% to 79 000 in the adult rat. The axon loss is most prominent during the second postnatal week, when 32 000 axons are climinated, but continues for several weeks at a slower rate.
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  • 24
    ISSN: 1432-0533
    Keywords: Somatostatin ; Immunohistochemistry ; Aganglionosis ; Man ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The distribution of somatostatin-like immunoreactive (SOM-LI) nerves was elucidated immunohistochemically in the gut tissues from patients with Hirschsprung's disease and congenital aganglionosis rats. In the normoganglionic human colon, SOM-LI nerve cell bodies were found to a greater extent in the submucous plexus and to a lesser extent in the myenteric plexus. However, they were rarely observed in both the plexuses of the oligoganglionic segment. SOM-LI nerve fibres were widely distributed in the aganglionic bowel. The circular muscle layer of the distal aganglionic segment was densely innervated by SOM-LI nerve fibres which are probably derived from the extrinsic, hypertrophic nerve bundles. A decreased number of the intramuscular nerves fibres were seen in the proximal aganglionic segment. In the colon and rectum from adult and 21-day-old rats, SOM-LI cell bodies were numerous in both plexuses. On the other hand, enteric neurons were completely lacking from the colon and rectum of congenital aganglionosis rats of 21 days old. No neuronal elements staining for SOM were disclosed in these aganglionic segments of mutant rats. A possible origin and pathophysiological role of the extrinsic nerve fibres containing SOM in the diseased bowel are discussed. It is concluded that SOM-LI nerves in the human distal colon comprise both intrinsic and extrinsic elements, while SOM nerves in the rat colon and rectum are of only intrinsic origin.
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  • 25
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    Anatomy and embryology 179 (1989), S. 435-442 
    ISSN: 1432-0568
    Keywords: Ultrastructure ; In vitro fertilization ; Bovine ; Ova ; Cortical granules
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Heifers were superovulated by PMSG or FSH, and oestrus was induced by prostaglandin. One group of animals was ovariectomized 19–26 h after the LH peak, the content of preovulatory follicles aspirated, and the oocytes processed for in vitro fertilization. Another group was inseminated and ova were collected from the oviducts for study of in vivo fertilization. All ova were examined ultrastructurally. The developmental rate following in vitro fertilization was delayed compared to fertilization in vivo. A high proportion of the in vitro fertilized ova showed polyspermic penetration of the zona pellucida, and supernumerary spermatozoa were found in the ooplasm of some ova. In vivo fertilization was associated with release and subsequent dispersal of the cortical granule content in the perivitelline space. In contrast to this the released granule content of the in vitro fertilized ova remained undispersed close to the oolemma. This feature may account for the high incidence of polyspermic penetration of the zona pellucida. In addition, the study provided an ultrastructural visualization of the initial contact between the equatorial segment of the spermatozoon and the microvilli of the oocyte, and the subsequent internalization of the sperm head.
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  • 26
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    Anatomy and embryology 179 (1989), S. 449-456 
    ISSN: 1432-0568
    Keywords: Corticospinal tract ; Development ; Myelination ; Pyramidal tract ; Anterograde tracing ; Electronmicroscopy ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Horseradish-peroxidase was used to anterogradely label and thus to trace the growth of corticospinal axons in rats ranging in age from one day to six months. Three to eight HRP-gels were implanted in the left cerebral hemisphere of the cortex. In each spinal cord three levels were studied, the cervical intumescence (C5), the mid-thoracic region (T5) and the lumbar enlargement (L3). The methodology employed for the electron microscopic visualization of HRP has been described previously (Joosten et al. 1987a). The outgrowth of labelled unmyelinated corticospinal tract axons in the rat spinal cord primarily occurs during the first ten postnatal days. The outgrowth of the main weve of these fibres is preceded by a number of pathfinding axons, characterized by dilatations at their distal ends, the growth cones. By contrast, later appearing unmyelinated axons, which presumably grow along the pathfinding axons, do not exhibit such growth cones. The first labelled pioneer axons can be observed in the cervical intumescence at postnatal day one (P1), in the mid-thoracic region at day three (P3) and in the lumbar enlargement at day five (P5). Prior to the entrance of the axons, the prospective corticospinal area or the pre-arrival zone is composed of fascicles consisting of unlabelled, unmyelinated fibres surrounded by lucent amorphous structures. During the outgrowth phase of the corticospinal fibres some myelinated axons could be observed within the outgrowth area even before day 14. These axons, however, were never labelled. These findings strongly suggest that the outgrowth area, which is generally denoted as the pyramidal tract, contains other axons besides the corticospinal fibres (and glial cells). The process of myelination of the labelled corticospinal tract axons in the rat spinal cord starts rostrally (C5) at about day 14 and progresses caudally during the third and fourth postnatal weeks. Although myelination seems to be largely complete at day 28 at all three spinal cord levels, some labelled unmyelinated axons are still present in the adult stage.
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  • 27
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    Anatomy and embryology 179 (1989), S. 497-501 
    ISSN: 1432-0568
    Keywords: Parotid gland ; Ultrastructure ; Amylase ; Secretion ; Isoproterenol
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The effects of continuous light on ultrastructural organization and sympathetic secretory responses of the rat parotid gland are reported. After 50 days of continuous light exposure, the fine structure of the parotid gland exhibited features of enhanced secretory activity as judged by the striking development of rough endoplasmic reticulum and Golgi complexes, the depletion of secretory granules and the increased turnover of secretory cells. The secretory responses of parotid gland to isoproterenol revealed that continuous light induced a 30% increase in amylase release. This secretory hyperactivity appears to be related to a postsynaptic supersensitivity of sympathetic fibers of the autonomic nervous system.
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  • 28
    ISSN: 1432-0568
    Keywords: Sympathetic ganglion ; Binucleate cells ; Ultrastructure ; Feulgen staining ; Computerized image analysis ; DNA
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The relative proportion, ultrastructure and DNA-content of the binucleate cells in the celiac superior mesenteric ganglion of the guinea pig was studied using light and electron microscopy as well as computerized image analysis of Feulgen stained cells. The number of mono — versus binucleate cells was found to vary with stage of development with about 40% of the cells being binucleate in adult animals and 50% in late prenatal stage. No difference in ultrastructure was observed between the nuclei of the two cell types. The binucleate cells contain twice the amount of DNA found in the mononucleate cells.
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  • 29
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    Anatomy and embryology 179 (1989), S. 591-604 
    ISSN: 1432-0568
    Keywords: Fetus ; Membranes ; Placenta ; Green monkey ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary This study examined developmental changes in fetal membranes and placenta of Cercopithecus aethiops from a Carnegie developmental stage 12 embryo to nearterm fetuses. Ultrastructurally, yolk sac cells (endoderm and mesothelium) were similar to comparable stages in other primates. Endodermal cells had few apical microvilli, abundant rough-endoplasmic reticulum, electron dense mitochondria and dense bodies. In contrast, mesothelial cells were squamous with numerous microvilli, small mitochondria and a few short strands of rough endoplasmic reticulum. Amnion cells early in gestation were squamous with few microvilli, large glycogen deposits and poorly developed cytoplasmic components. Tight junctions and desmosomes held adjacent cells together. The basal surface was smooth and the basal lamina was distinct. As development proceeded the amniotic cells became cuboidal and possessed numerous microvilli. Cytoplasmic organelles were better developed and glycogen deposits increased by mid-gestation. A thick layer of microfibrils and collagen fibers was prominent below the basal lamina. Near-term, the glycogen had virtually disappeared and the amount of lipid droplets increased. Basal infoldings and podocytic processes and the extracellular matrix had increased. The smooth chorion consisted of pseudostratified columnar cells. Cells had short microvilli, numerous granules and vesicles of variable size and electron density in early gestation. With increasing age, amounts of granules and vesicles decreased, as the endoplasmic reticulum became prominent. The chorionic trophoblast was a continuous layer in mid-pregnancy and its cells had well-developed organelles and inclusions. Late in gestation, the trophoblastic layer became discontinuous and wide intercellular spaces and channels were present. In the placenta, the trophoblastic elements showed features characteristic of primate placenta.
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  • 30
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    Anatomy and embryology 180 (1989), S. 103-108 
    ISSN: 1432-0568
    Keywords: Ultrastructure ; Gut ; Endocrine cells ; Testudo graeca ; Chelonia
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The digestive tract of Testudo graeca (Chelonia) was investigated by means of electron microscopy using both conventional and immunocytochemical techniques. EC-, L-, D-, G-, B-, N- and EC-L-cells were detected. These cells share several common ultrastructural characteristics with the endocrine cells of mammals (i.e. clear cytoplasm, prominent Golgi apparatus, secretory granules etc.). EC and D1 cells have so far not been described in the esophagus of any animal species; in the present study these cells have been observed in the esophagus of T. graeca. Of special interest was the presence of B-cells in the intestine, suggesting that the migration of B-cells from the gut to the pancreas to constitute pancreatic islets is not concluded in T. graeca. The present study demonstrates that the gut endocrine system of T. graeca is a complex structure containing a large variety of endocrine cell types similar in morphology to those found in higher vertebrates.
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  • 31
    ISSN: 1432-0568
    Keywords: Monkey ; Ultrastructure ; Pinealocytes ; Axon terminals ; Synapses
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The present study described the normal ultrastructure of the monkey pineal gland. The gland was composed of the principal pinealocytes, intramural neurons and glial cells. The nucleus of the pinealocytes was deeply infolded with evenly distributed chromatin materials. The abundant cytoplasm was rich in organelles including the well-developed Golgi apparatuses, multivesicular bodies, dense-cored vesicles and widely scattered free and polyribosomes. A variety of axon terminals was observed and the majority of them contained pleomorphic agranular vesicles with a few large dense-cored vesicles. A few terminals showed flattened vesicles or small dense cored vesicles. Some of the axon terminals formed synaptic contacts with the cell bodies of pinealocytes. These synapses were mainly concentrated in the posterior third of the gland. The occasional intramural neurons observed were postsynaptic to axon terminals containing round agranular vesicles. The sources of the nerve fibres and terminals forming synaptic junctions with pinealocytes and intramural neurons were discussed.
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  • 32
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    Anatomy and embryology 180 (1989), S. 207-212 
    ISSN: 1432-0568
    Keywords: Thyrotroph (TSH cell) ; Anterior pituitary ; Immunogold electron microscopy ; Postnatal development ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Thyrotrophs (TSH cells) of the rat anterior pituitary identified by immunogold electron microscopy were classified into three subtypes according to their morphological characteristics: Immature type TSH cells are oval with a few small secretory granules (50–100 nm in diameter) and poorly developed cell organelles. These cells are frequently found in the neonatal stage between birth and 10 days of age. The intermediate type is polygonal or stellate, containing a moderate number of medium sized secretory granules (80–120 nm in diameter) and moderately or well developed cell organelles. Cells of this type are often found between 10 and 30 days of age. Mature type cells are large and polygonal in shape, and contain many large secretory granules (120–180 nm in diameter) and well developed cell organelles. Cells of the last type are frequently found at more than 30 days of age. At 45 days of age the mature type TSH cells make up about 70% of all TSH cells. The proportion of immature type cells was shown to decrease while the proportion of the mature type TSH cells increases, as the animal grows.
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  • 33
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    Anatomy and embryology 180 (1989), S. 243-257 
    ISSN: 1432-0568
    Keywords: Dorsal lateral geniculate nucleus ; Synapse formation ; Synaptic glomerulus ; Rat ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Synapse formation and maturation were examined in the rat dorsal lateral geniculate nucleus (dLGN) from birth to adulthood. Examination of animals, whose ages were closely spaced in time, showed that the maturation of the synaptic organization of the nucleus takes place chiefly during the first 3 weeks of postnatal life. This period of maturation may be divided into 3 broad stages. During the first stage, which spans the first 4 days of life, there are only a few immature synapses scattered throughout the nucleus; occasionally aggregates of 3 or 4 synapses are encountered. Dendrodendritic synapses first appear at the end of this stage. The second stage, which lasts from the end of the first stage through day 8, is characterized by intensive synaptogenesis as well as extensive growth and degeneration. For the first time, large boutons resembling retinal terminals form multiple synaptic contacts with dendrites and dendritic protrusions; these synaptic arrangements are partially covered by glial processes. A feature characteristic of the developing dLGN during the first 2 postnatal weeks, and particularly during the second stage, is the presence of membrane specializations that resemble vacant postsynaptic densities. These specializations, which may be unapposed or opposite another neuronal process, decrease in frequency as the number of synapses increases. It is not known whether these densities are converted to synapses or whether they result from loss of presynaptic elements. The third stage in the process of synaptogenesis, which spans a period between days 10 and 20, is characterized by myelination and by the diminution of growth cones, degenerating profiles and vacant postsynaptic densities. There is also a very significant increase in the number and maturation of synapses including synaptic glomeruli. However, it is not until the end of this stage that synapses appear qualitatively indistinguishable from synaptic arrangements identified in adult animals.
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  • 34
    ISSN: 1432-0533
    Keywords: 2,4-Dithiobiuret ; Thioimidodicarbonic diamide ; Motor endplate ; Neuromuscular junction ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary 2,4-Dithiobiuret was given i.p. to rats for 4 days at a daily dosage of 1 mg/kg and the development of the lesion associated with neuromuscular dysfunction studied in hindlimb lumbrical muscles. The first morphological indication of neurointoxication was the appearance in some motor endplates of masses of branching tubular smooth endoplasmic reticulum (SER) on day 2 which correlated with the initial functional disturbances. By the 3rd day, most motor endplates were distended by accumulations of densecored, lucent and synaptic vesicles, abnormally swollen mitochondria, intermediate filaments and branching, tubular SER. Evidence of collateral axonal sprouting was seen first at this time. On days 4 and 5, many motor endplates were markedly enlarged and showed axoplasmic organelle congestion. A significant increase in synaptic vesicle size was noted at these times in some terminals. Interposition of Schwann cell processes between the pre- and postsynaptic membranes and terminal retraction was now evident. Some intramuscular nerves showed hydropic Schwann cell cytoplasm with separation of the outermost myelin lamellae, mitochondrial swelling and adaxonal vacuoles as early as the 1st day. Proliferation and segregation of SER around central cores of neurofilaments was seen in myelinated nerve fibres and preterminals on the 3rd day. At this and later times accumulations of SER and swollen mitochondria were found at sites of axonal varicosities and at the paranodal constrictions at nodes of Ranvier. These ultrastructural data are discussed with regard to reduced terminal Ca2+ content (demonstrated by oxalate-pyroantimonate cytochemistry) and compared with the sequelae of botulinum intoxication.
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  • 35
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    Acta neuropathologica 79 (1989), S. 336-339 
    ISSN: 1432-0533
    Keywords: AIDS ; Cytomembranous inclusions ; Tubuloreticular inclusions ; Ultrastructure ; Peripheral nerve
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary We report finding tubuloreticular inclusions (TRI) in the endothelial cells of endo- and epineurial vessels in the sural nerve of 11 patients with AIDS. Six patients had a painful peripheral neuropathy, one a non-painful sensory neuropathy, one an acute inflammatory demyelinating polyradiculoneuropathy and one a thalidomide-related neuropathy. Two patients had no clinical evidence of neuropathy. The TRI are not specific to one neuropathy and are unlikely to contribute to the pathogenesis of peripheral nerve syndromes in AIDS.
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  • 36
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    Anatomy and embryology 179 (1989), S. 221-226 
    ISSN: 1432-0568
    Keywords: GABA ; Immunocytochemistry ; Gastrointestinal tract ; Epithelium ; Enteroendocrine cells ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Frozen sections of the corpus ventriculi, antrum pyloricum, duodenum, jejunum, ileum and colon from animals perfusion fixed with glutaraldehyde were treated with an antiserum specific for glutaraldehyde-fixed GABA and processed by the peroxidase antiperoxidase method. Semithin plastic sections from the antrum pyloricum were treated similarly. Stained cells appeared in the epithelium of all segments examined except the corpus ventriculi. The highest density of cells was observed along the major curvature of the antrum pyloricum. Here they were located in the bottom half of the gastric glands. Many of the cells showed a process extending towards the glandular lumen. No significant staining in the epithelium appeared when the antiserum was preincubated with glutaraldehyde-GABA complexes, nor when the anti-GABA serum was exchanged with anti-glycine or preimmune serum. The present findings and previous physiological data suggest that GABA may play a role in gut endocrine regulation.
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  • 37
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    Acta neuropathologica 77 (1989), S. 654-658 
    ISSN: 1432-0533
    Keywords: Melanotic neuroectodermal tumor ; Immunohistochemistry ; Ultrastructure ; Pineal origin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary A case of a melanotic neuroectodermal tumor arising from pineal region of a 4-year-old girl is presented. The tumor had spread diffusely to the meninges, consistent with malignant behavior. Histologically, the tumor consisted primarily of epithelial elements arranged in tubules, cords and nests separated by fibrous vascular tissue in addition to a small neuroblastomatous focus. Melanin pigment was frequently observed in the epithelial tumor cells, and melanin-laden macrophages were also often observed. No teratoid elements were found. Immunohistochemically, tumor cells were positive for neuron-specific enolase but were nonreactive for S-100 protein, epithelial membrane antigen, glial fibrillary acidic protein, vimentin, α-fetoprotein and human chorionic gonadotrophin. Ultrastructurally, the epithelial nature of the tumor cells could be easily demonstrated. In addition, melanosomes in various stages in maturation were observed, indicating melanogenesis of the tumor. On the basis of the tumor location and the histological similarities previously observed for the fetal pineal body, it is very likely that this melanotic epithelial tumor could have originated from the fetal pineal gland.
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  • 38
    ISSN: 1432-0533
    Keywords: Gangliocytoma ; Ganglioglioma ; Ultrastructure ; Immunohistochemistry ; Neuroendocrine markers
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary We studied five cases of central nervous system neuronal tumor, one gangliocytoma and four gangliogliomas, both ultrastructurally and immuno-histochemically, using antibodies to neuroendocrine markers including tyrosine hydroxylase (TH), serotonin (5HT), somatostatin (SOM), met-enkephalin (MEK), leu-enkephalin (LEK), substance P (SP), gastrin, vasopressin, oxytocin, vasoactive intestinal polypeptide, adrenocorticotropic hormone and calcitonin. In all cases, the presence of dense-core vesicles (60–250 nm) in the neuronal elements was the characteristic ultrastructural finding. Synapses were observed in two cases. Immunohistochemically, variable numbers of neuronal cells showed positive staining for SOM in five cases, TH, MEK and LEK in three cases, and 5HT and SP in one case each. The others were negative. Positive immunoreactivity for multiple markers was shown in all cases. SOM, TH, 5HT and SP were present in the small- to medium-sized cells, while MEK and LEK were almost exclusively confined to the large cells. Our study clearly indicated that these tumors contained neuronal cells which were not homogeneous with regard to neuroendocrine markers.
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  • 39
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    Acta neuropathologica 77 (1989), S. 258-266 
    ISSN: 1432-0533
    Keywords: Neurofibrillary tangles ; Alzheimer's disease ; Pick bodies ; Immunohistochemistry ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary We have studied the immunohistochemical reactivity and ultrastructure of both neurofibrillary tangles (NFTs) occurring with severe neurofibrillary diseases, and Pick bodies (PBs) associated with Pick's disease. The NFTs and PBs did not react immunohistochemically with the anti-nonphosphorylated neurofilament monoclonal antibody irrespective of whether they were pretreated with alkaline phosphatase. In granular neurons of the dentate fascia of Ammon's horn in cases of dementia of the Alzheimer type (DAT), NFTs either resembled PB-like inclusion bodies (Horoupian's inclusion bodies) in form, or had a perinuclear structure. Immunohistochemically and ultrastructurally, the NFTs in the dentate fascia in cases of DAT, including Horoupian's inclusion bodies, were similar to the NFTs in the pyramidal neurons of Ammon's horn, which are found most frequently in association with severe neurofibrillary diseases. Under a light microscope, Horoupian's inclusion bodies and PBs could not be differentiated and appeared to be argyrophilic round cytoplasmic inclusions in granular neurons of the dentate fascia. There were, however, ultrastructural differences. Horoupian's inclusion bodies consisted of bundles made up of straight tubules (STs), each about 15 nm in diameter. These bundles were intermixed with a few paired helical filaments which occurred at intervals of about 80 nm. On the other hand, PBs were composed of randomly distributed 15-nm-wide STs, intermixed with a very few fibrillary structures. These fibrils had a periodicity of about 160 nm, and ranged in width from about 15 nm to 30 nm. Horoupian's inclusion bodies associated with DAT and PBs associated with Pick's disease are different in this neuropathological aspect. The NFTs, including Horoupian's inclusion bodies in the dentate fascia in cases of DAT, are considered to be a manifestation of neurofibrillary degeneration.
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  • 40
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    Acta neuropathologica 79 (1989), S. 86-93 
    ISSN: 1432-0533
    Keywords: Primary malignant CNS lymphoma ; Ultrastructure ; Intracytoplasmic tubuloreticular, membranous structures ; Intranuclear inclusions
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Ultrastructural studies of 17 primary malignant CNS lymphomas revealed 6 tumors with abnormal intracytoplasmic and/or intranuclear membranous structures, most frequently, associated with the endoplasmic reticulum or perinuclear envelope. In most cases, tubuloreticular inclusions and paired cisternae were present. Less frequent were accumulation of mictotubules, concentric lamellar bodies, and rod-like or paracrystalline intranuclear inclusions. The specificity and significance of these membranous structures remain questionable because of their frequent occurrence in a variety of normal and pathological conditions. Some of these changes may be considered as cellular reactions to viral infections, others may indicate cellular activity or degeneration.
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  • 41
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    Acta neuropathologica 79 (1989), S. 149-153 
    ISSN: 1432-0533
    Keywords: Lead ; Rat ; Cerebellum ; Particle-induced X-ray emission (micro-PIXE)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The distribution of lead in the cerebellum of suckling Sprague-Dawley rats was examined using a nuclear microprobe for elemental mapping of tissue sections (particle-induced X-ray emission, 3-μm beam of 2.5 MeV protons; micro-PIXE). The rats were injected intraperitoneally with a lead-containing vehicle or vehicle only from ages 1 to 14 days. The calculated doses were 7.8 (low-dose) and 15.6 (high-dose) μg lead/g body weight. The rats were killed at 20 days of age. The vascular system was rinsed quickly with 0.15 M ammonium acetate to obtain determinations of intra-parenchymal lead with minimal influence of lead bound to erythrocytes and plasma proteins. Brains were frozen in propane/propylene in liquid nitrogen. Cryostat sections, 15 μm thick, were air dried on formvar coats that covered a hole, 15 mm in diameter, in a plastic disc, and were used for lead analysis by micro-PIXE. Very low concentrations of lead were found in the brain of controls. Lead levels in homogenates from cerebrum and cerebellum measured by atomic absorption spectrometry (AAS) were: low-dose 1.2–2.2 μg/g wet weight and high-dose 1.4–2.4 μg/g wet weight. The lead levels measured with the micro-PIXE method were in good agreement with the levels found with AAS. Lead was present in the cerebellar white matter in two to three times higher amounts than in the cortical grey (low-dose white matter 11–18 μg/g dry weight, grey matter 2.0–5.5 μg/g dry weight). This was true for both low and high dose exposed rats. Lead concentrations in rats subjected the high-dose lead exposure were approximately 60% higher than those in low-dose exposed rats. Concentrations were lower in the Purkinje cell layer than in other parts of the cortex. These new findings on the distribution of lead in suckling rats are discussed in relation to the pathogenesis of experimental lead encephalopathy.
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  • 42
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    Archives of dermatological research 281 (1989), S. 35-39 
    ISSN: 1432-069X
    Keywords: Pseudo-Kaposi's sarcoma ; Bluefarb-Stewart syndrome ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary An ultrastructural study of the skin lesion of a young patient affected by pseudo-Kaposi's sarcoma of the Bluefarb-Stewart type (BSS) is reported. The neoplasm consisted of a proliferation of vascular structures mostly consisting of a solid bud of endothelial cells surrounded by a thinned and polystratified basement membrane and several pericytes. Both endothelial cells and pericytes were of normal ultrastructural appearance. Intervascular “stromal” cells were few and morphologically identified as macrophages and/or phagocytic fibroblasts. Masses of hemosiderin were detected outside the cells and in the macrophages, endothelial cells, and pericytes. Intracytoplasmatic crystalloid inclusions similar to those found in fetal endothelium and hemangiomas were observed in a few endothelial cells. These findings are different from those of previously reported cases of pseudo-Kaposi's sarcoma and may be helpful in distinguishing Kaposi's sarcoma from BSS. The role of immunodeficiency in the onset of BSS is discussed.
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  • 43
    ISSN: 1432-0428
    Keywords: Islet amyloid polypeptide ; Pancreatic islets ; B cells ; Ultrastructure ; Immunocytochemistry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Islet amyloid polypeptide is a novel 37 amino-acid-residues polypeptide which has been isolated from amyloid deposits in an insulinoma, and in human and cat islets of Langerhans. The molecule has 46% homology with the calcitonin gene-related peptide. Light microscopy examination of the pancreas shows that islet amyloid polypeptide immunoreactivity is restricted to the islet B cells. The present study utilized a rabbit antiserum against a synthetic peptide corresponding to positions 20–29 of islet amyloid polypeptide, a sequence without any amino-acid identity with calcitonin gene-related peptide. By applying the immunogold technique at the ultrastructural level, it was shown that both insulin and islet amyloid polypeptide immunoreactivity occurs in the central granular core of the human B cell secretory granules, while the A cells remain unlabelled. The demonstration that islet amyloid polypeptide is a granular protein of the B cells may indicate that it is released together with insulin. Further studies are necessary to evaluate the functional role of islet amyloid polypeptide.
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  • 44
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    Development genes and evolution 198 (1989), S. 92-102 
    ISSN: 1432-041X
    Keywords: Vitellogenesis ; Xenopus oocyte ; Yolk-platelet membrane ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The yolk platelets ofXenopus laevis have been studied by thin-section and freeze-fracture electron microscopy to characterize the boundary membrane during yolk formation. Throughout vitellogenesis, large yolk platelets are in close contact with smaller nascent yolk organelles. Two types of primordial yolk platelets (I and II) have been discriminated. After membrane fusion these precursors can be completely incorporated into the main body of existing platelets, numerous yolk crystals then merge and form one uniformly stratified core. Lipid droplets are tightly attached to the membrane at all developmental stages of yolk platelets. A direct connection of endoplasmic reticulum to the membranes of yolk platelets was not observed. On freezeetching replicas, yolk-platelet membranes present fracture faces with intramembranous particles (IMP) of various sizes and a heterogeneous distribution of approximately 200–600 IMP/μm2 at the E face, and 1200–2100 IMP/μm2 at the P face. Again, this presentation of the membrane exhibits neither anastomoses to the endoplasmic reticulum, nor caveolae that exclude the uptake of yolk-containing vesicles into these yolk organelles. Proteinaceous yolk platelets tend to fracture along their periphery through the superficial layers.
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  • 45
    ISSN: 1432-1106
    Keywords: Collateral sprouting ; Nerve regeneration ; Mechanoreceptors ; C-fibers ; Plasma extravasation ; Evans blue ; Skin ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The capacity of the saphenous nerve for collateral sprouting was examined by electrophysiological recordings of the activity of low threshold mechanoreceptors and plasma extravasation after C-fiber stimulation in rats. When the sciatic nerve was sectioned neonatally or in adults little evidence was obtained for collateral sprouting of either mechanoreceptors or fibers involved in plasma extravasation in the intact saphenous nerve0 In rats where the sciatic nerve was sectioned and the saphenous nerve was crushed either neonatally or in adults, expansive regenerative reinnervation by thin fibers, but not mechanoreceptors, was observed particularly in glabrous skin. Saphenous crush alone did not cause expansive regenerative reinnervation. The results indicate that much of the collateral sprouting or regenerative reinnervation of the skin observed in morphological studies may represent the presence of fibers not responding to the stimuli used in the present study. It is also suggested that some observations of collateral sprouting may represent changes in responsiveness to stimulation of skin areas with overlapping innervation territories.
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  • 46
    ISSN: 1432-1106
    Keywords: Hippocampus ; Noradrenaline ; Habenula ; Microdialysis ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Hippocampal extracellular levels of noradrenaline (NA) were monitored with the microdialysis technique during electrical stimulation of the lateral habenula (LHb) in halothane anaesthetized rats. The steady state NA level was 20.8±4.6 fmole/15 min of perfusion (mean ± SEM). Electrical stimulation of the LHb for 15 min (15 Hz, 0.5 mA) induced an immediate 228±48% increase in hippocampal NA release, compared to the pre-stimulation baseline (p〈0.05). A second stimulation 90 min later induced a similar increase. The effect of LHb stimulation was completely abolished by a knife cut transecting the dorsal NA bundle either immediately rostral to the locus coeruleus or at the level of the parafascicular nucleus. This suggests that the effect was dependent on nerve impulses flow in the coeruleo-hippocampal NA neurons, and was not mediated, e.g., by a local spread of electricity into the hippocampus. Since the LHb has previously been shown to be a powerful activator of the mesencephalic raphe nuclei we tested whether the effect was mediated via the serotonergic system. However, the effect of LHb stimulation on hippocampal NA release persisted after 5,7-di-hydroxytryptamine treatment and after complete radiofrequency lesions of the dorsal and central superior raphe nuclei. The present data suggest that electrical stimulation of the LHb can increase hippocampal NA release through an activation of the locus coeruleus, and that this effect is not dependent on the mesencephalic raphe nuclei. The results support the role of the LHb as a link for limbic and striatal forebrain activation of brain stem monoaminergic systems.
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  • 47
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    Experimental brain research 76 (1989), S. 369-385 
    ISSN: 1432-1106
    Keywords: Cobalt experimental epilepsy ; Motor cortex ; GABA ; Immunocytochemistry ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The distribution of GABA-immunoreactive cell bodies and terminals was studied using an anti-GABA serum during the development of chronic focal epilepsy induced by cobalt deposits onto the motor cortex of the rat. Cell counts of GABA-positive neurons were carried out in the epileptogenic area and correlated with the electrophysiological activity of the cobalt focus. In normal control rats, we identified GABA-immunoreactive somata and processes in the motor agranular cortex; they were multipolar or bipolar but never pyramidal and were present in all layers, especially in layer II. GABA-immunoreactive terminals were widely scattered in the neuropil and surrounded the unlabelled cell bodies. In the cobalt-treated animals, changes in the GABAergic innervation were observed during the development of the epileptic focus: decreases in the GABA-positive cell density and in the number of GABA-positive terminals were present before the onset of epileptic discharges and became more marked during the period of maximal spiking activity; a progressive return to normal values of GABA-positive cell density (except in the deep layers) as well as the reappearance of GABA positive terminals were associated with the extinction of the epileptic syndrome. Our observations suggest that the impaired inhibitory neurotransmission mediated by GABA plays a role in the development of the cobalt-induced epilepsy; moreover the recovery of GABAergic function which occurs during the extinction of the epileptic syndrome might imply a capacity for axonal regeneration of the GABAergic neurons.
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  • 48
    ISSN: 1432-1106
    Keywords: Calcitonin gene-related peptide (CGRP) ; Bed nucleus of the stria terminalis ; Central nucleus of the amygdala ; Ultrastructure ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Light and electron microscopic analysis of calcitonin gene-related peptide (CGRP)-like immunoreactive (LI) terminals in the bed nucleus of the stria terminalis (BST) and the central nucleus of the amygdala (Ce) was carried out using the peroxidase-antiperoxidase method. CGRP-LI fibers were densely distributed in the dorsal subdivision of the lateral BST (BSTL) and the lateral and lateral capsular subdivisions of the Ce, where the CGRP-LI terminals formed symmetrical and asymmetrical axo-dendritic, and symmetrical axosomatic synapses. One of the most characteristic features of the CGRP-LI terminals was the presence of large, long boutons, each of which surrounded a cell soma and made many synaptic contacts. These findings suggest that CGRP exerts a significant influence on neurons in the BSTL and Ce.
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  • 49
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    Experimental brain research 77 (1989), S. 499-506 
    ISSN: 1432-1106
    Keywords: Temporal/entorhinal area ; Memory processing ; Neurotransmitters ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The purpose of the present study was to investigate whether effects of temporo-entorhinal disconnections on acquisition and retention of a visual discrimination task might be associated with neurochemical dysfunctions. The results revealed that the present lesions impaired both acquisition and retention of the discrimination task. This impairment was accompanied by decreased glutamergic activity in both temporal and entorhinal cortices. No changes were seen in levels of acetylcholine or GABA. Further, the distribution of glutamate/ aspartate was related to both regional and hemispheric differences. The results are discussed in terms of a highly integrative role of the lateral entorhinal cortex and in terms of other putative neurotransmitter systems involved in the function of memory.
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  • 50
    ISSN: 1432-1106
    Keywords: Ventrobasal thalamic neurones ; Noxious mechanical stimulation ; Orofacial receptive fields ; Trigeminal sensory complex ; Tractotomy ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Single units were recorded, using extra-cellular glass microelectrodes, in the ventrobasal complex of the thalamus of rats under halothane-nitrous oxide anaesthesia. The animals had previously undergone a large bilateral section of the trigeminal sensory complex just above the obex to deprive the caudal part of the trigeminal sensory complex (subnucleus caudalis) of its trigeminal afferents. As observed on frontal slices our lesions impaired the whole descending tract and, in most cases, the intratrigeminal pathways between the rostral and the caudal part of the complex. Forty-seven units responding to a somatic mechanical noxious stimulation applied to the trigeminal area were recorded in these conditions. Forty-two of these had a receptive field (or at least a part of it) in or around the oral and nasal cavities, and 5 in the peripheral part of the face. These data confirm the hypothesis that the rostral part of the trigeminal sensory complex participates in pain sensory pathways, as a first relay site between nociceptive primary afferents coming from oral, perioral and perinasal areas, and the ventrobasal complex of the thalamus. In addition, they suggest that the intra-trigeminal pathways are not essential for the transmission of these nociceptive inputs, to the lateral thalamus.
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  • 51
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    Experimental brain research 78 (1989), S. 233-242 
    ISSN: 1432-1106
    Keywords: Hoppocampus ; Granule cells ; Long lasting inhibition ; Frequency habituation ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary In paired pulse stimulation experiments the mechanism underlying frequency habituation of postsynaptic potentials in dentate granule cells of rat hippocampal slices was studied by measuring extra and intracellular potentials as well as changes in extracellular calcium ([Ca2+]0) and potassium concentrations ([K+]0). Orthodromic stimulation of the perforant path induced in most granule cells a late, slow hyperpolarization (SH), lasting for up to 1.2 s. During the SH the membrane conductance was increased by up to 40%. The reversal potential of the SH was around -90 mV and varied with the [K+]0. Frequency habituation was seen in all cells with the SH, whereas cells which display frequency potentiation had no SH. Lowering of [Ca2+]0 reversed paired pulse induced frequency habituation into frequency potentiation at [Ca2+]0 levels where the SH disappeared. Phaclofen blocked the SH and reversed frequency habituation into frequency potentiation. Elevating [Mg2+]0 also reversed frequency habituation into frequency potentiation and reduced the SH. We conclude that the SH represents a late, slow IPSP which is responsible for frequency habituation in dentate granule cells. We noted that during repetitive stimulation the SH soon started to fade. This effect can in part be attributed to extracellular K+-accumulation as suggested by the K+-dependence of the slow IPSP and the observations of changes in [K+]0 during repetitive stimulation. This could explain why frequency habituation reverses into frequency potentiation during repetitive stimulation.
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  • 52
    ISSN: 1432-1106
    Keywords: Extincton ; Nonreward ; Adrenoceptor ; Noradrenaline ; Stress ; Sympathetic nervous system ; 6-hydroxydopamine ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary We tested whether the stress of nonreward has neurochemical effects on noradrenergic neurones which resemble those reported for other forms of stress. Rats trained to run in a straight runway for food reward were subjected to either 1 or 10 extinction trials. Half the rats in each group were injected before the start of acquisition with IP 6-hydroxydopamine to deplete peripheral noradrenaline stores. All animals were killed immediately after their final test in the runway, together with untrained controls. Noradenaline depletion had no behavioural or neurochemical effects. The rate of extinction in the 10-trial group, which was indexed by the slope of the linear regression of running time on trial, correlated negatively with both alpha2 and beta-adrenoceptor number (Bmax). There were no differences between groups in cerebral cortical noradrenaline content, or alpha2 or beta-adrenoceptor binding. These results substantially conflict with those predicted from Stone's hypothesis relating beta-adrenoceptor sensitivity to the behavioural response to stress. A further finding was that alpha2, but not beta-adrenoceptor number, negatively correlated with levels of noradrenaline in the tissue, suggesting that noradrenaline is less involved in the regulation of beta than in that of alpha2-adrenoceptors.
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  • 53
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    Experimental brain research 76 (1989), S. 141-152 
    ISSN: 1432-1106
    Keywords: Abducens motoneurones ; Intracellular recordings ; HRP staining ; Membrane properties ; Somato-dendritic organization ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The electrical and morphological properties of abducens motoneurones were investigated in the rat with intracellular recordings and intracellular HRP-staining. Motoneurones were identified by their antidromic response to electrical stimulation of the lateral rectus muscle. The antidromic action potential was followed by a delayed depolarization and an after hyperpolarization lasting 20 ms to 45 ms. The whole neurone input resistance (RN) calculated from I/V curves, was found to lie between 2 MΩ and 15 MΩ with a bimodal distribution (mean values 4.9 MΩ and 12 MΩ). In some cases, anomalous rectification was observed with low current intensities. Prolonged hyperpolarizing current pulses revealed the presence of a time dependant inward rectification and slow rebound depolarization. The intensity/frequency curves suggest the existence of three ranges of discharge. The average intensity frequency slope during the steady state was 43 imp/s/ nA. Eight abducens motoneurones were intracellularly labelled with HRP and fully reconstructed. The soma (23 μm to 40 μm in diameter) gave off 5 to 7 primary dendrites. The general organization and extension of the dendritic trees depended on the location of the soma within the abducens nucleus. The mean diameter of primary dendrites was 4.17 μm with similar average values in all motoneurones. The soma size of abducens motoneurones was not correlated with either the size of the proximal tree or the whole neurone input resistance.
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  • 54
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    Experimental brain research 76 (1989), S. 646-650 
    ISSN: 1432-1106
    Keywords: Glutamate binding sites ; Autoradiography ; Vestibular nuclei ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Quantitative autoradiography has been used to characterize l-[3H] glutamate binding sites and to describe their distribution in frozen sections of rat vestibular nuclei. Scatchard plots and Hill coefficients of glutamate binding suggest that glutamate interacts with a single population of sites having a KD of about 126 nM and a capacity of 2.5 pmol/mg of protein. Although the level of glutamate binding was not very high compared to the highest levels described for some other brain regions, it was nonetheless substantial. The sites were distributed unevenly in the four vestibular nuclei and their distribution correlated well with the projection areas of the vestibular nerve, which has been described as a glutamate-mediated pathway. The highest numbers of glutamate binding sites were observed in the medial vestibular nuclei. This technique provides a very sensitive assay for characterizing the pharmacological subtypes of glutamate binding in the vestibular nuclei and for analyzing changes in these sites during development or after deafferentation of the vestibular nuclei.
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  • 55
    ISSN: 1432-1106
    Keywords: Somatosensory cortex ; Differential development ; Lectin binding ; Vibrissae ; Forepaw ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Physiological studies have demonstrated a highly organized somatotopic representation of the body surface in SI cortex of rat. This representation is correlated morphologically with the presence of barrel-shaped structures in layer IV. Conventional staining techniques reveal barrels in the latter part of the first postnatal week. Recently, the peroxidase conjugates of lectins, which recognize glycosylated molecules, have been used to study barrel field formation. Con A, for example, has been shown to bind primarily to prospective barrel sides and septa as early as postnatal day 3 (PND-3) in mouse. To date, investigations of SI cortex using the lectin (Arachis hypogaea) peanut agglutinin (PNA) have been confined to the study of the barrel field representation of the face and mystacial vibrissae in the mouse. In the present study we extend these findings to the development of the representation of the entire body surface called the rattunculus. Rats ranging from PND-1 (first 24 h after birth) to PND-12 were anesthetized with Nembutal and perfused with 4% paraformaldehyde and 2% glutaraldehyde in 0.2 M sodium cacodylate buffer. Brains were removed, flattened tangentially, and sectioned on a vibratome at 30–120 microns. Sections were blocked in TRIS-buffered saline (TBS) plus 2% bovine serum albumin and incubated in peanut lectin at 4° C. Following incubation, sections were washed with TBS and processed using peroxidase histochemistry. Lectin binding in the prospective forelimb representation was apparent by PND-5 whereas lectin binding to the prospective face-mystacial vibrissae representation occurred before PND-4. These results suggest that body part representations show individual variations during early pattern formation. In rat, the representation of the limbs may lag behind the representation of the face-mystacial vibrissae during early postnatal development. This developmental gradient within the cortex may reflect a differential expression of lectin receptors.
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  • 56
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    Experimental brain research 78 (1989), S. 646-648 
    ISSN: 1432-1106
    Keywords: Hippocampus ; Experimental epilepsy ; Paroxysmal depolarization shift ; Afterpotential ; Penicillin ; Ca2+-activated potassium ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Penicillin-induced paroxysmal depolarization shifts (PDS) are followed by prolonged afterhyperpolarizations of about 2 seconds duration. Intracellular injection of EGTA blocked a late component of the afterhyperpolarizations; an early one lasting up to one second was only slightly reduced by EGTA. It is concluded that afterhyperpolarizations following penicillininduced PDS comprise different components: an initial one lasting up to one second which is not Ca2+-dependent and a slow one lasting up to two seconds which is caused by a Ca2+-dependent K+ current.
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  • 57
    ISSN: 1432-1106
    Keywords: Inhibition ; Hippocampal formation ; Development ; GABAergic neurons ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Glutamate decarboxylase (GAD)-positive and Golgi impregnated local circuit neurons of the hippocampal formation of five day old rats were examined in light and electron microscopic preparations. The ultrastructural features of these neurons were similar in both the dentate gyrus and CA1 area of Ammon's horn. Somata displayed a perikaryal cytoplasm rich in organelles but lacked organized Nissl bodies. Most nuclei showed intranuclear infoldings of varying degrees but no intranuclear sheets or rods were found. Somata and dendrites were contacted by relatively immature axon terminals that formed mainly symmetric synapses. The axons of local circuit neurons in both the dentate gyrus and Ammon's horn formed symmetric synapses with somata and dendrites of the principal neurons in these regions. Thus, both GAD-positive and Golgi-impregnated terminals of local circuit neurons were observed to form synapses with pyramidal and granule cells. These terminals were usually small and contained relatively few pleomorphic synaptic vesicles. The results show that a circuitry for inhibition is established in the 5 day old dentate gyrus and Ammon's horn, even though the local circuit neurons lack some of the typical adult ultrastructural features at this age.
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  • 58
    ISSN: 1432-1106
    Keywords: Steroid receptor ; CRF ; Neurotensin ; Enkephalin ; CCK ; PHI ; VIP ; Somatostatin ; TRH ; Dopamine ; Immunohistochemistry ; Arcuate nucleus ; Hormones ; Neurosecretion ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The paraventricular nucleus (PVN) of male albino rats was analyzed for the presence of glucocorticoid receptor-like immunoreactivity (GR-LI) in neuropeptide containing neurons. Using immunohistochemistry, coronal sections trough the entire PVN were double-stained with a mouse monoclonal antibody against GR and one of the following antisera: rabbit antiserum to corticotropin releasing factor (CRF), neurotensin (NT), enkephalin (ENK), cholecystokinin (CCK), thyrotropin releasing hormone (TRH), galanin (GAL), peptide histidine isoleucine (PHI), vasoactive intestinal polypeptide (VIP), somatostatin (SOM) or tyrosine hydroxylase (TH). For comparison the occurrence of GR-LI in NT-, SOM-, NPY- or TH-positive neurons of the arcuate nucleus was also studied. Our results indicate that GR-LI is present in the parvocellular part of the PVN but not in its magnocellular portion. Virtually every parvocellular neuron in the PVN containing one of the above mentioned peptides was also positive for GR, with the exception of SOM neurons, of which only about two thirds showed detectable levels of GR-LI. All TH-positive, presumably dopamine neurons in the PVN were GR-positive. In the arcuate nucleus all TH- and NPY-positive neurons as well as a large proportion of the SOM- and NT-immunoreactive neurons contained GR-LI. The results indicate that in the PVN, in addition to the CRF neurons, certain peptidergic neurons in the parvocellular part of the PVN, without any established role in the control of ACTH synthesis and release, may also be under glucocorticoid control. This seems to be the case also for most arcuate neurons.
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  • 59
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    Experimental brain research 78 (1989), S. 164-173 
    ISSN: 1432-1106
    Keywords: Glia ; GFAP ; Brainstem ; Spinal cord ; Immunocytochemistry ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The topographical mapping of glial fibrillary acidic protein (GFAP)-immunoreactivity was performed in coronal serial sections of the rat mesencephalon, rhombencephalon and spinal cord. Relative to a background of poor or moderate overall staining of the mesencephalon, the interpeduncular nucleus, substantia nigra and the periaqueductal grey matter were prominent by their intense GFAP-immunoreactivity. The pons and particularly the medulla contained more GFAP-labelled elements compared with the mesencephalon. The spinal trigeminal nucleus and Rolando substance were distinguished by their intense staining. Large fibre tracts were usually poor in immunoreactive GFAP. In a concluding discussion, findings relevant to the GFAP-mapping of the whole rat CNS are evaluated with regard to possible reasons underlying the observed differential distribution of GFAP-immunoreactivity.
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  • 60
    ISSN: 1432-1106
    Keywords: Cardiopulmonary vagal reflex ; Bezold-Jarisch reflex ; Excitatory amino acid ; Caudal ventrolateral medulla ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The importance of the caudal ventrolateral medulla (CVLM) in mediating vagal cardiopulmonary (Bezold-Jarisch reflex) reflex activity was studied in urethane-anaesthetized rats. Unilateral electrolytic lesion of the CVLM markedly attenuated Bezold-Jarisch reflex responses (hypotension and bradycardia) elicited by intravenous injections of 5-HT. Bilateral lesion of the CVLM virtually abolished the reflex responses. Microinjection of the excitatory amino acid (EAA) receptor antagonist kynurenate (KYN), but not the inactive analogue xanthurenate, into the CVLM markedly attenuated the reflex responses to 5-HT. The N-methyl-D-aspartate (NMDA) receptor antagonist, MK-801 also markedly attenuated reflex activity. Furthermore, lesions, KYN and MK-801 all tended to elevate resting blood pressure and to reduce resting heart rate. These findings support the hypothesis that the CVLM is an important medullary locus mediating cardiovascular reflex integration and that an EAA synapse in the CVLM is important in the cardiopulmonary reflex arc.
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  • 61
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    Experimental brain research 78 (1989), S. 358-368 
    ISSN: 1432-1106
    Keywords: Neurotensin ; Frontal cortex ; In vitro slice preparation ; Intracellular recording ; Single-electrode-voltage-clamp ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The actions of neurotensin (NT) on frontal pyramidal neurons were studied in vitro in slices of rat cerebral cortex using current clamp and single electrode voltage clamp (SEVC) techniques. Bath application of NT (0.1 μM–10 μM) induced a depolarization (2–13 mV) in 88% of the pyramidal cells, this effect was associated with a decrease in input conductance of 5–35% and its reversal potential was estimated at -88 +/-9.7mV. Typically, this depolarizing effect of NT was transient, since no cell responded to a second application of the peptide within 20 min after the first one. NT also induced an increase in the rate of firing of pyramidal cells evoked by direct stimulation, even when an hyperpolarizing current was applied to prevent the depolarization induced by NT. This effect could neither be explained by a decrease of the post-spike after-hyperpolarization, nor by an increase of the persistent sodium current which sustains the spiking of pyramidal cells, since the former was not affected consistently by NT and the later was insensitive to the peptide. This excitation of pyramidal neurons by NT persisted after blockade of synaptic transmission. On the other hand, NT also enhanced the synaptic noise recorded in pyramidal cells in standard perfusing medium. Furthermore, dopaminergic antagonists and noradrenergic antagonists failed to block these effects of NT. Finally, the inactive fragment of the peptide, NT(1–8), did not affect membrane properties of pyramidal cells. All together, these results suggest that NT excites frontal cortical neurons through the activation of specific NT receptors.
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  • 62
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    Experimental brain research 74 (1989), S. 41-46 
    ISSN: 1432-1106
    Keywords: Cortico-cortical neurons ; Sensorimotor cortex ; Glutamate and aspartate immunoreactivity ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Retrograde transport of tracers and immunocytochemistry have been used to determine if association and callosal neurons in the primary motor and somatosensory cortex of rats contain high levels of glutamate or aspartate and may, thus, use these amino acids as neurotransmitter. After tracer injections in these areas, about 65% of the retrogradely labeled neurons in layer V in the ipsilateral or contralateral hemisphere are immunopositive for glutamate. Lower percentages of double-labeled neurons are found in layers III, VI, and II. Similar results are obtained when sections are processed for aspartate immunoreactivity. About 90% of retrogradely labeled neurons are immunopositive in sections incubated with a mixture of both glutamateand aspartate antisera. These results suggest that a large fraction of cortico-cortical neurons are immunoreactive for either one amino acid but not for both. It is proposed that neurons with high levels of one amino acid use this as neurotransmitter; high levels of glutamate and aspartate are likely to be present in a fraction of neurons which may release both amino acids or a substance closely related to these.
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  • 63
    ISSN: 1432-1106
    Keywords: α-melanocyte ; stimulating hormone ; Dopamine receptors ; Rat ; Hypothalamus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Release of alpha-melanocyte-stimulating hormone (α-MSH) from slices of rat hypothalamus superfused with artificial cerebro-spinal fluid (ACSF) was quantified by radioimmunoassay. Addition of 10-6 M quinpirole, a D2-dopamine receptor agonist, to the superfusion medium caused a significant (P 〈 0.001) reduction in the amount of α-MSH released upon depolarisation with 50 mM potassium from 319 ±37% to 110 ±16% of basal release in normal ACSF (mean ±S.E.M.). Basal peptide release in the presence of quinpirole was unaffected. Sulpiride, a D2-dopamine receptor antagonist, at a concentration of 10-6 M, induced a significant (P 〈 0.05) increase of both basal and potassium-stimulated α-MSH release to 203 ±21% and 447 ±88% of basal release in normal ACSF respectively. The latter increases were abolished when sulpiride and quinpirole were added in combination. SK&F 38393-A and SCH 23390, a D1-dopamine agonist and antagonist respectively, had no significant effect on either basal or potassiumstimulated α-MSH release. It is proposed that endogenous dopamine exerts an inhibitory control on α-MSH release from the rat hypothalamus via D2-dopamine receptors and that in isolated hypothalamic slices there is a tonic inhibition of peptide release due to the activity of this system.
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  • 64
    ISSN: 1432-1106
    Keywords: Hippocampal mossy fibers ; GABAergicneurons ; GABAergic inhibition ; EM immunocytochemistry ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Mossy fibers are known to form excitatory synapses on pyramidal neurons in regio inferior of the hippocampus. This study demonstrates that the mossy fibers also establish synaptic contacts with glutamate decarboxylase-immunoreactive, supposedly GABAergic inhibitory neurons in the CA3 region. The observed connection provides a morphological basis for feed-forward inhibition of the pyramidal cells.
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  • 65
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    Experimental brain research 75 (1989), S. 543-554 
    ISSN: 1432-1106
    Keywords: Intralaminar nuclei ; Cortical projection ; Arousal ; Pain ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Cortical surface potentials evoked from thalamic intralaminar nuclei have been studied in rats anaesthetized with chloralose. Stimulation with low current intensity in central lateral nucleus (CL), evoked potentials in large areas of the rat isocortex. In the posterior parietal cortex responses with a short latency negativity were evoked which followed high frequency repetitive stimulation. Its latency and ability to follow high frequency stimulation indicated a monosynaptic connection from CL to this part of the cortex. The short latency potential was followed by a second negativity with longer latency and varying amplitude. This second negativity did not follow repetitive stimulation exceeding 10 Hz, and was also reduced by supplementary doses of anaesthetics, indicating a polysynaptic origin. Stimulation at different CL sites elicited cortical potentials with short latency in a topographical pattern. Laminar analysis in the parietal and motor cortex suggested both a superficial and a deep layer termination of afferents from CL. Similar topografical relations and afferent layer distributions have previously been found in cats. The role of the thalamocortical projection from CL to parietal cortex in arousal, attention and pain mechanisms is discussed.
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  • 66
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    Experimental brain research 76 (1989), S. 417-423 
    ISSN: 1432-1106
    Keywords: Choline acetyltransferase ; Cerebral cortex ; Immunohistochemistry ; Development ; Transient expression ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The cholinergic innervation of the rat cerebral cortex was examined in pre- and postnatal life using immunohistochemistry with a monoclonal antibody directed against choline acetyltransferase (ChAT). Our observations show that there are two separate phases in the development of the cholinergic innervation of the rat neocortex. The first, a transient phase, occurs in the late stages of gestation and in the perinatal period. During this time, ChAT-labelled cells (neuroblasts, as well as immature pyramidal and non-pyramidal neurons) are present throughout the entire rostro-caudal extent of the primordial cortex. The fate of these cells, which are not visible shortly after birth, is unknwon as is their functional role in the developing cortex. The second phase in the development of the cholinergic innervation begins in the middle of the second postnatal week. At this stage only a few faintly stained neurons and fibres appear in the cortex. Their numbers and staining intensity increase gradually until the fifth postnatal week when ChAT-labelled neurons and axonal arbours appear indistinguishable from their adult counterparts. The pattern of development observed in the second phase parallels closely that shown in a recent analysis of cortical ChAT activity during postnatal life.
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  • 67
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    Experimental brain research 76 (1989), S. 656-661 
    ISSN: 1432-1106
    Keywords: Central chemoreceptor ; Carbon dioxide ; Nucleus tractus solitarius ; Nucleus ambiguus ; Cardiopulmonary control ; Brain slice ; Intracellular recording ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary To identify central sites of potential CO2/H+-chemoreceptive neurons, and the mechanism responsible for neuronal chemosensitivity, intracellular recordings were made in rat tissue slices in two cardiopulmonary-related regions (i.e., nucleus tractus solitarii, NTS; nucleus ambiguus, AMBc) during exposure to high CO2. When the NTS was explored slices were bisected and the ventral half discarded. Utilizing such “dorsal” medullary slices removed any impinging synaptic input from putative chemoreceptors in the ventrolateral medulla. In the NTS, CO2-induced changes in firing rate were associated with membrane depolarizations ranging from 2–25 mV (n = 15). In some cases increased e.p.s.p. activity was observed during CO2 exposure. The CO2-induced depolarization occurred concomitantly with an increased input resistance ranging from 19–23 MΩ (n = 5). The lower membrane conductance during hypercapnia suggests that CO2-induced depolarization is due to a decreased outward potassium conductance. Unlike neurons in the NTS, AMBc neurons were not spontaneously active and were rarely depolarized by hypercapnia. Eleven of 12 cells tested were either hyperpolarized by or insensitive to CO2. Only 1 neuron in the AMBc was depolarized and it also showed an increased input resistance during CO2 exposure. Our findings suggest that CO2/H+-related stimuli decrease potassium conductance which depolarizes the cell and increases firing rate. Although our in vitro studies cannot guarantee the specific function of these cells, we believe they may be involved with brain pH homeostasis and cardiopulmonary regulation.
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  • 68
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    Experimental brain research 77 (1989), S. 283-294 
    ISSN: 1432-1106
    Keywords: Intracellular recordings ; Membrane potential ; Input impedance ; Hippocampal pyramidal cells ; Theta rhythm ; Urethane ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Intracellular recordings were made from hippocampal pyramidal cells identified by their depths and their responses to commissural stimulation. Recordings were made during spontaneous bouts of hippocampal theta rhythm in urethane anesthetized rats. Membrane potentials (V m) of pyramidal cells varied with the phase of the theta rhythm, that is, there was an “intracellular theta rhythm”. The changes in V m averaged about 2 mV peak to peak. Averaged intracellular theta waves showed that CA1 pyramids were most depolarized at the time of the positive peak of the extracellular theta rhythm recorded in (and superficial to) the CA1 pyramidal cell layer (CA1 theta). Peak depolarizations for CA3/4 pyramids were more broadly distributed, but occurred mainly in the interval just before the positive peak to just before the negative peak of the CA1 theta. Input impedance minima that were measurable at frequencies as high as 100 Hz occurred at about the same phases of the extracellular theta rhythm as the peak depolarizations (positive-going zero crossing to negative-going zero crossing of the CA1 theta). Such impedance changes imply conductance changes on the soma. The magnitude and localization of the conductance changes suggests that somatic IPSPs make major contributions to the intracellular theta rhythm. The phase relation between the intracellular and extracellular theta rhythms could be reversed by long duration current pulses that depolarized the cells slightly. This implies that either the intracellular theta-related IPSPs are depolarizing potential changes, or that they occur simultaneously with EPSPs. The phase of the intracellular theta rhythm was generally unaffected by long duration hyperpolarizing current pulses. Chloride leakage that reversed the evoked IPSPs usually had no effect on the phase of the intracellular theta rhythm, although in one case it appeared to cause its amplitude to increase.
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  • 69
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    Experimental brain research 77 (1989), S. 234-244 
    ISSN: 1432-1106
    Keywords: Development ; Visual cortex ; Slicecultures ; Pyramidal cells ; GABA immunohistochemistry ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Slice cultures from the visual cortex of young rats were prepared using the roller culture technique (Gähwiler 1984). After 10 days in vitro the cortical cultures flattened to 1–3 cell layers, surviving for up to 12 weeks. The cultures were organotypically organized, the typical layered structure of the cortex was preserved. The neuronal composition of slice cultures was studied using intracellular staining, Golgi impregnation and GABA immunohistochemistry. Both pyramidal cells and several types of nonpyramidal cells were identified in the slice cultures. Electrophysiological recordings showed that the electrical properties of cells in culture were similar to those measured in acute slice preparations; for some cells, however, the spontaneous activity was higher. The maintained activity was strongly increased by application of the GABA antagonist bicuculline and decreased by GABA, suggesting that GABAergic inhibition is present in these preparations. We could observe the postnatal maturation of some characteristic morphological features in culture. For example, pyramidal cells in 6 day-old rats in situ have very short basal dendrites with growth-cones, and the dendrites are free of spines. After 2–3 weeks in culture growth-cones were no longer observed. Instead, the cells had developed a large basal dendritic field and the dendrites were covered with spines. Slice cultures therefore may provide a useful tool for physiological, anatomical, pharmacological and developmental studies of cortical neurons in an organotypical environment.
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  • 70
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    Experimental brain research 77 (1989), S. 295-301 
    ISSN: 1432-1106
    Keywords: Preoptic area ; Intrinsic neuron ; GABA ; Local neuron ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Neurons intrinsic to the preoptic area might participate in the control of neuroendocrine or behavioral events. To determine their existence and features, we deafferented the preoptic area of female rats, using completely circumscribing cuts with a Halasz knife. Despite obvious signs of degeneration of synapses originating from nerve cell bodies outside the preoptic island, some synapses survived complete deafferentation. We saw synaptic contacts not only on the neuronal cell body, but also on the dendritic shaft and spine. There were no peculiar morphological features, as might suggest unique physiologic functions of these intrinsic synapses. The prominence of intrinsic synapses in the preoptic area suggests that, in addition to hormone effects on preoptic neurons, and long ascending afferents, intrinsic synapses might play significant roles in neuroendocrine controls.
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  • 71
    ISSN: 1432-1106
    Keywords: Met- and leu-enkephalin ; Morphine ; Cortex ; Intracellular recordings ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The action of enkephalin-analogues (D-ala2-D-leu5-enkephalin and D-ala2-D-metenkephalin) and morphine, iontophoretically applied, was tested on rat cortical neurons intracellularly recorded “in vivo”. Inhibition of cellular excitability of 60% of the tested cells followed the iontophoretic administration of opioid peptides. 50% of the inhibited cells were also hyperpolarized. The amplitude of membrane hyperpolarization was related to the value of the membrane potential. In 13 out of the 30 inhibited cells the change in membrane input resistance was measured; the input resistance was decreased by 30%. In 8 cells, hyperpolarized by the opioid peptides, the depolarizing postsynaptic potentials, evoked by cortical stimulation, were also reduced in amplitude. Naloxone, iontophoretically applied, reversed and/or prevented the peptide responses. On the same neurons, morphine induced a bursting pattern of spiking activity and increased the membrane input resistance: this action was naloxone-insensitive. The reported results suggest that opioid peptides and morphine activate, respectively, naloxone-sensitive and naloxone-insensitive mechanisms on the same cortical neurons, leading to different and, in some respect, opposite effects on the neuronal activity.
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  • 72
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    Experimental brain research 77 (1989), S. 374-380 
    ISSN: 1432-1106
    Keywords: GABAA and GABAB receptors ; Rhythmic activity ; G-protein ; Pertussis toxin ; Septo-hippocampal pathway ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The possible involvement of GABA in the control of the rhythmical bursting activity (RBA) of septo-hippocampal neurons (SHNs) has been studied in the rat in vivo. The discharge frequency of SHNs was modified by the iontophoretic application of a GABA agonist and antagonist as well as by the application of the GABA uptake blocker, nipecotic acid. The GABAB agonist baclofen inhibited the SHNs' activity, this effect being antagonized by the GABAB antagonist phaclofen. However, these different pharmacological manipulations did not modify the RBA frequency. Pretreatment of the rats with pertussis toxin, a substance which is known to block the events mediated by G-proteins (Gi or Go), decreased the RBA frequency. Neither agonists nor antagonists of GABAA or GABAB types had significant effects on the rhythmical bursting activity of SHNs. The effect of pertussis toxin suggests that other neurotransmitters or intrinsic mechanisms involving a G-protein influence this rhythm.
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  • 73
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    Experimental brain research 76 (1989), S. 12-20 
    ISSN: 1432-1106
    Keywords: Distribution ; Ultrastructure ; Biopsy ; Catecholamines ; Interneurons
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary In freshly fixed biopsies of human cerebral cortex obtained at surgery, immunocytochemical staining with antibodies against tyrosine hydroxylase (the rate limiting biosynthetic enzyme for catecholamines) revealed, in addition to a dense axonal plexus, a population of immunoreactive cell bodies. The neuronal nature of these cells was ascertained by: i) the presence of a rich rough endoplasmic reticulum in the cell body and of synapses on the cell body and dendrites, and ii) the demonstration of the lack of reactivity with the astroglial marker, glial fibrillary acidic protein, in the tyrosine hydroxylase-immunoreactive cells. The tyrosine hydroxylase-immunoreactive neurons were found in all areas of cortex sampled, and were located almost exclusively in the infragranular layers. Most tyrosine hydroxylase-immunoreactive cells were bipolar and were vertically oriented, but a few had a multipolar or horizontal dendritic arbor. The dendrites of these cells were varicose and aspiny, and the axons were very thin. Tyrosine hydroxylase-immunoreactive neurons were reported to be present transiently in the developing mammalian cerebral cortex and only recently in cerebral cortex of mature mammalian brains. Internuncial neurons in the human cerebral cortex containing a catecholamine synthesizing enzyme would be significant, in particular considering that catecholamines are likely to be involved in some major mental disorders.
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  • 74
    ISSN: 1432-1106
    Keywords: Caudate-putamen ; Neural plasticity ; Nigrostriatal projection ; Sensory deprivation ; Vibrissae ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The influence of unilateral removal of vibrissae on the crossed and uncrossed nigrostriatal projections was examined with the horseradish peroxidase tract tracing technique. Hemivibrissotomy mainly affected the projections arising from the rostral part of the substantia nigra. One to three days after clipping the vibrissae, rats were found to have more labeled neurons in the crossed projection to the caudate-putamen (CPU) on the same side as vibrissae removal than in the crossed projection to the CPU opposite to vibrissae removal. A reversed asymmetry was seen in rats examined 4–20 days after vibrissae removal. These animals had more labeled cells in the crossed and uncrossed projections terminating in the CPU opposite to the shaved side, i.e. in the hemisphere deprived of vibrissal sensory input. This time-course of neural alterations is similar to that of the recovery from behavioral asymmetries seen after hemivibrissotomy. Similar time-dependent alterations in the nigrostriatal projection had been found after unilateral injection of 6-OHDA into the substantia nigra.
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  • 75
    ISSN: 1432-1106
    Keywords: Parvalbumin ; GABA ; Nonpyramidal cell ; Monoclonal antibody ; Lectin ; Cerebral cortex ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Monoclonal antibody VC1.1 is shown to stain selectively a subpopulation of GABAergic neurons in the rat cerebral cortex. Almost all VC1.1 immunoreactive cells were also GABA-like immunoreactive (GABA-LI) and parvalbumin (PV) immunoreactive, whereas they were about 30% and 65% of GABA-LI and PV-positive cells in the parietal cortex and about 13% and 32% in the occipital cortex, respectively. Although a few VC1.1 positive cells showed somatostatinlike and/or cholecystokinin-like immunoreactivities, they were exceptional (less than 1% of VC1.1 positive cells). Furthermore about 90% of VC1.1 positive cells were also stained with a lectin, Vicia villosa agglutinin, with a specific affinity for terminal N-acetylgalactosamine.
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  • 76
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    Experimental brain research 78 (1989), S. 214-218 
    ISSN: 1432-1106
    Keywords: Nigral grafts ; Adrenal grafts ; Rotation ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Separate groups of rats with unilateral 6-OHDA lesions of the nigrostriatal pathway received intrastriatal foetal (E14) substantia nigra suspension grafts, intrastriatal postnatal (P22–25) adrenal medulla suspension grafts using either collagenaseor trypsin-based dissociation procedures, intraventricular adrenal medulla grafts, or remained with lesions alone. Rats with nigral or adrenal suspension grafts, but not rats with adrenal solid grafts, showed reduced apomorphine-induced rotation in comparison with lesion rats. The nigral graft group alone showed substantial reduction of amphetamine-induced rotation, and this was the only group manifesting good long-term graft survival. These results indicate that nigral and adrenal grafts do not have comparable mechanisms of functional action, and suggest that adrenal grafts can ameliorate apomorphine-induced rotation by a non-specific mechanism.
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  • 77
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    Naunyn-Schmiedeberg's archives of pharmacology 340 (1989), S. 239-245 
    ISSN: 1432-1912
    Keywords: Intestinal absorption ; Vascular perfusion ; Glucuronidation ; 1-Naphthol ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Using the isolated vascularly fluorocarbon emulsion perfused rat small intestine some factors which determine the extent of the intestinal glucuronidation of 1-naphthol to 1-naphthol-β-d-glucuronide were studied. Increasing the luminal 1-naphthol concentration resulted in a concomitant increase in the 1-naphthol appearance in the vascular perfusate. In contrast, the total appearance of 1-naphthol-β-d-glucuronide increased less than proportional to the increase in the luminal 1-naphthol concentration. About 88% of the total amount of 1-naphthol-β-d-glucuronide excreted was released into the vascular perfusate. The capacity-limited intestinal glucuronide efflux is most likely due to saturation of the excretory mechanism for 1-naphthol-β-d-glucuronide. Decreasing the vascular flow rate influenced both the appearance of 1-naphthol and 1-naphtol-β-d-glucuronide in the vascular perfusate, whereas the appearance of 1-naphthol-β-d-glucuronide in the luminal perfusate was essentially flow-independent. A noradrenaline-induced change in the haemodynamic state of the vascular bed (with the total flow kept constant) resulted in a marked decrease in the 1-naphthol vascular concentration. The vascular 1-naphthol-β-d-glucuronide concentration was only slightly affected. These results indicate that changes in blood flow and blood flow distribution within the intestinal wall can affect the extent of presystemic intestinal metabolism by interfering with the absorption of the parent compound and the efflux of formed conjugates. These parameters can be of paramount importance for causing variable intestinal first-pass effects of drugs in vivo.
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  • 78
    ISSN: 1432-1912
    Keywords: Intestinal absorption ; 1-Naphthol ; Glucuronidation ; Rat ; Albumin binding
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Using an isolated vasculary perfused rat small intestine we studied the role of luminal flow rate and intraluminal binding on the absorption of 1-naphthol (1-N) and the intestinal metabolism of 1-N to 1-naphthol-β-d-glucuronide (1-NG). Raising the luminal perfusion rate resulted in a decrease in the luminal 1-N extraction ratio and an increase in the luminal 1-N clearance Cl lum. The dependency of Cl lum on flow rate appeared to conform to a convective diffusion model. A differential susceptibility of 1-N absorption and the total 1-NG appearance to the luminal flow rate resulted in a flow-dependent first-pass effect of 1-N. Next, the effect of intraluminal binding on 1-N disposition was studied in experiments in which albumin was added to the luminal perfusion fluid. The unbound concentration, as the driving force for the uptake of 1-N, seems not to be rate-limiting for the appearance of 1-NG. The total appearance of 1-NG in the presence of albumin was greater than would be anticipated from the free concentration of 1-N. As a result the extent of presystemic extraction increased with increasing albumin concentration. The precise mechanisms responsible for the phenomenona are not entirely clear. Consideration of the heterogeneity in the glucuronidation capacity along the rat small intestine and along the crypt-villus axis can help to explain the obtained results.
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  • 79
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    Pflügers Archiv 413 (1989), S. 217-224 
    ISSN: 1432-2013
    Keywords: Rat ; Kidney ; Uptake ; Transport ; α-Ketoglutarate ; Luminal ; Basolateral ; Production
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract In order to establish the characteristics of net renal transport and utilization of α-ketoglutarate (α-KG) in the rat, we have precisely quantified the renal blood flow, the urinary flow and the rates of α-KG delivery, filtration, reabsorption or secretion, excretion, uptake or production by an in vivo rat kidney preparation. In normal rats, α-KG uptake was higher than α-KG reabsorption at both endogenous and elevated plasma α-KG concentrations; thus, a net peritubular transport, which was the main supplier of α-KG to the renal cells, took place. Saturation of reabsorption and peritubular transport of α-KG occurred at blood α-KG concentrations about 30 and 150 times above normal, respectively. Acute metabolic acidosis was found to have no effect on renal handling of α-KG. At endogenous plasma α-KG concentrations, alkalosis converted net renal uptake into net renal production of α-KG resulting in addition of α-KG by the renal cells both to blood and to the luminal fluid. Elevation of blood α-KG concentration restored the renal uptake of α-KG. This uptake, which was entirely accounted for by the peritubular transport of α-KG, reached a maximum which was lower than that observed in normal and acidotic rats.
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  • 80
    ISSN: 1432-2013
    Keywords: Rat ; Skeletal muscle ; Development ; Ionic conductances ; Denervation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The development of membrane ionic conductances of rat extensor digitorum longus (EDL) muscle fibers was studiedin vitro using intracellular recordings. At 7–8 days after birth, the potassium conductance (GK) dominated the total membrane conductance while the chloride conductance (GC1) was very low. A rapid increased of GC1 towards adult values was observed after few days (12–14 day old rats), whereas GK did not decrease up to day 23. Denervation at 7–8 days after birth suppressed the maturation of the electrical parameters measured, and 15 days after the nerve crush, GC1 was just detectable. These results suggest that the maturation of the electrical properties, and in particular that of the resting chloride conductance in mammalian striated muscle fibers, occurs during the first weeks of postnatal life and is dependent on innervation.
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  • 81
    ISSN: 1432-2013
    Keywords: Amiloride ; Bumetanide ; Cl-secretion ; Electrical field stimulation ; Large intestine ; Na-absorption ; Rat ; Stripping ; Submucosal plexus ; Tetrodotoxin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The initial phase of in vitro experiments in Ussing-type chambers on large intestine is characterized by short-circuit currents (ISC) declining from high starting values to a lower plateau within 0.5 h. The origin of this “initial ISC-transient” was investigated by ISC measurements on partially stripped segments of rat rectal colon. Transport was pre-stimulated in vivo by keeping animals in barbiturateanesthesia for 5 h prior to tissue preparation. This procedure caused by endogenous aldosterone-liberation amiloride-sensitive Na-absorption to become the predominant electrogenic transport. The initial ISC-transient was abolished by tetrodotoxin (TTX, 1 μM), indicating a neuronal mediation of this phenomenon. In order to identify the transport which was subject to neuronal control, the amiloride-sensitive Na-absorption was measured during electrical field stimulation (bipolar rectangular pulses: 5 Hz, 1 ms, ±6 mA). There was no difference to unstimulated controls. In contrast, the initial ISC-transient was dependent on Cl in the bath following Michaelis-Menten-kinetics (K M=20 mM) and could be prevented by 10 μM serosal bumetanide. Then, initial filling of the Ussing-chamber was imitated during the course of the experiment by removal and immediate readdition of the bathing fluid. This procedure caused ISC-changes of similar appearance as the initial ISC-transient. To verify that indeed mechanical stretch is the sensory stimulus triggering the initial ISC-transient, the effect of small pressure oscillations was studied. This also produced an ISC-transient which was TTX-sensitive and was abolished after removal of the submucosal plexus Meissner by total stripping. It is concluded that amiloride-sensitive Na-absorption does not contribute to the initial transient and is not affected by the enteric nervous system. Initial ISC-transients asobserved during the first half hour of Ussing experiments are due to electrogenic Cl-secretion which is stimulated by mechanical stretch during tissue preparation and filling of the chamber via a submucosal neuronal reflex pathway. The possible biological meaning of this stretch-induced secretory process could be facilitation of transit during imminent stasis of the gut contents.
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  • 82
    ISSN: 1432-2013
    Keywords: Fast-twitch muscle ; Chronic stimulation ; Contractil properties ; Parvalbumin ; Sarcoplasmic reticulum ; Ca2+-uptake ; Rat ; Rabbit
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract This study compares changes in contractile properties, Parvalbumin content, and Ca2+-uptake by the sarcoplasmic reticulum (SR) of low-frequency stimulated rat and rabbit tibialis anterior (TA) muscles. Time to peak tension increased 1.8-fold in 35-day stimulated rabbit TA, while no change occurred in rat TA. Isometric twitch tension increased 2-fold in rabbit TA, but was unaltered in rat TA. Parvalbumin (PA) content was more than 90% reduced in rabbit TA, but only 60% in rat TA after 35 days. At this time, PA content of the stimulated rat TA was still higher than that of normal rabbit TA. Taking into account the suggested role of PA as a cytosolic Ca2+ buffer, its decrease could lead to an impaired free Ca2+-decay with a prolonged active state and a higher tension output during a single twitch. This would explain why chronic stimulation led to an increase in isometric twitch tension in rabbit TA, but not in rat TA. The 1.6-fold rise in half-relaxation time of 35-day stimulated rat and rabbit TA most likely resulted from a 50% reduced Ca2+-uptake by the SR, due to a still unknown modification of the Ca2+-transport ATPase.
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    Pediatric nephrology 3 (1989), S. 149-155 
    ISSN: 1432-198X
    Keywords: Cationized bovine serum albumin ; Glomerular capillary wall polyanion ; Serum sickness glomerulopathy ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The effects of injected native and cationized bovine serum albumin (BSA− and BSA+ respectively) were evaluated in rats which subsequently received anti-BSA. Thrombocytopenia, low creatinine clearance (Ccr), increased proteinuria, capillary swelling, mild tuft necrosis and BSA+ deposits in glomeruli resulted within 24 h of BSA+ injection. Later BSA+ produced mesangial expansion glomerular capillary wall (GCW) thickening and deposits of BSA+ accompanied by rabbit anti-BSA and rat anti-BSA which correlated well with small mesangial, subendothelial and subepithelial electron-dense granular accumuli. These latter enlarged considerably after the injection of anti-BSA. BSA− controls showed minimal or no lesions. The disappearance from the blood (t1/2) of a single dose of immune complexes (IC) prepared with chromatography-purified, radioiodinated anti-BSA-BSA− and BSA+ was determined in another group of rats. The t1/2 of BSA− anti-BSA was 42.8 h (95% confidence: 39.8–46.2) while that of BSA+ anti-BSA was 52.5 h (48.1–57.8). These results suggested that serum sickness glomerulitis developed only in rats injected with BSA+, due to in situ IC which presumably grew by accretion of foreign anti-BSA. Circulating IC may have developed and colocated with the latter, with dissociation and recombination at these sites. It is postulated that the functional-immunomorphological changes and the slow removal of cationized IC reported herein could be explained by the highly positive net charge of the injected antigen.
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    Psychopharmacology 97 (1989), S. 35-39 
    ISSN: 1432-2072
    Keywords: Delta-sleep-inducing peptide (DSIP) ; Paradoxical sleep (PS) ; Phosphorylated analogue of DSIP ; Rat ; Sleep substance ; Slow wave sleep (SWS)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Continued 10-h nocturnal intracerebroventricular infusion of 0.5 nmol P-DSIP, the phosphorylated analogue of delta-sleep-inducing peptide (DSIP), significantly increased slow wave sleep (22%) and paradoxical sleep (81%) in unrestrained rats. The increase in the amount of sleep was largely due to an increase in the number of sleep episodes. Larger and smaller doses were ineffective in doses ranging from 0.025 to 25 nmol. The sleep-promoting potency of P-DSIP was 5 times greater than that of DSIP compared by the same assay.
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  • 85
    ISSN: 1432-2072
    Keywords: Social memory ; Cholinomimetic drugs ; Nootropic drugs ; Benzodiazepine inverse agonists ; Psychostimulants ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The recognition of an unfamiliar juvenile rat by an adult rat has been shown to imply short-term memory processes. In this study the effect of various psychotropic drugs on this investigatory behaviour was examined. The procedure was as follows: an unfamiliar juvenile rat was placed in the home cage of an adult rat for 5 min. The time spent by the adult rat in investigating the juvenile was recorded. The adult rat was then immediately treated with vehicle or test compounds, and was again exposed for 5 min to the same juvenile 2 h later. At this time point vehicle-treated rats no longer recognized the juvenile rat, i.e. the time of investigation was similar to that observed during the first presentation. Arecoline (1 and 3 mg/kg IP), physostigmine (0.05 and 0.1 mg/kg SC), RS86 (0.5 mg/IP) and nicotine (0.125 and 0.5 mg/kg IP) reduced in a dose-dependent fashion the time spent in investigating the juvenile during the second exposure. This result cannot be attributed to nonspecific effects, since it was not observed when a different juvenile was used for the second exposure. The effect of arecoline was reversed by scopolamine, but not by methylscopolamine. Aniracetam reduced investigatory behaviour at the dose of 50 mg/kg IP. FG 7142 (5 mg/kg IP) and β-CCM (0.4 mg/kg IP) were also active and their effect was reversed by Ro 15-1788. dl-Amphetamine (0.5 and 1 mg/kg IP), nomifensine (1.25–10 mg/kg IP) and strychnine (0.25 and 0.5 mg/kg IP) were ineffective or reduced this behaviour unspecifically. Social recognition may therefore represent a useful and simple test to detect compounds which enhance short-term, olfactory, memory and to assess in the same animals the specificity of this activity.
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    Psychopharmacology 97 (1989), S. 521-528 
    ISSN: 1432-2072
    Keywords: Trimethyltin ; Delay conditioning ; Conditioned flavor aversion ; Passive avoidance ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Trimethylin (TMT) produces behavioral and cognitive deficits resulting, in part, from limbic system toxicity. To determine whether these effects result from learning deficits or accelerated memory loss, the present experiment examined two delay conditioning paradigms in rats previously treated with either saline or TMT. Saline-treated Long-Evans rats receiving injections of lithium after consuming saccharin-flavored water later avoided saccharin ingestion: the degree of avoidance varied inversely with the time (0.5, 3 or 6 h) separating initial saccharin availability and lithium injection. Rats treated with TMT (8 mg/kg IV, 30 days prior) showed impaired conditioning at the long but not the short or intermediate delay conditions, suggesting that the deficits were mnemonic and not associative. Similar delay-dependent deficits in rats treated with TMT were observed in a passive avoidance task that arranged one of two delays between response emission and shock delivery during training. The effects of TMT on delay conditioning were accompanied by reduced bodyweight and hippocampal pathology. In summary, TMT appears to alter the temporally dependent association of events (entering darkened compartment versus saccharin consumption) and consequences (foot shock versus lithium administration) during acquisition. Furthermore, the observed deficits in delay conditioning produced by TMT did not appear to be task specific, with similar effects determined with tests of both somatosensory and gustatory avoidance learning designed to distinguish between functional alterations due to deficits in memorial processes from those due to altered sensory, motor, or associative processes.
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  • 87
    ISSN: 1432-2072
    Keywords: Anxiety ; Social interaction ; Plus-maze ; 5HT3 receptors ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The effects of three 5HT3 receptor antagonists: BRL 43964 (0.1 and 1 mg/kg, oral), GR 38032F (0.1 and 1 mg/kg, oral), and zacopride (0.01, 0.1 and 1 mg/kg, IP) were examined in low light test conditions of the social interaction test. None of the three 5HT3 receptor antagonists had a significant effect on social interaction. In contrast, in two experiments chlordiazepoxide (7.5 mg/kg) significantly increased social interaction and this effect was greatest in the unfamiliar test condition. In a third experiment, the effects of GR 38032F (0.1 and 1 mg/kg, oral) and zacopride (0.01, 0.1 and 1 mg/kg, oral) were investigated in the high light test conditions of the social interaction test; neither compound had a significant effect. In the elevated plus-maze, chlordiazepoxide (7.5 mg/kg oral or IP) significantly increased both the per cent number of entries made onto open arms and the per cent of time spent on the open arms, indicating an anxiolytic action. Zacopride (0.01, 0.1 and 1 mg/kg, oral or IP) had no significant effect in this test. The effect of the baseline rate of responding in the social interaction test on the effects of 5-HT3 antagonists is discussed. The results from the present experiment and those from other animal tests of anxiety caution against the conclusion that 5HT3 receptor antagonists are anxiolytic.
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  • 88
    ISSN: 1432-2072
    Keywords: Apomorphine ; Dopamine ; Penile reflex ; Sexual behavior ; Spinal cord ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Relatively high doses of systemically administered apomorphine inhibit penile reflexes. It is possible that these inhibitory effects are due, at least in part, to actions of apomorphine on the lumbosacral spinal cord. The present experiments examined this possibility by injecting apomorphine (10 and 50 μg/5.0 μl vehicle) into the lumbosacral subarachnoid space through chronic, indwelling cannulae. Such injections impaired ex copula penile reflexes, slowed the rate of copulation, and decreased the number of intromissions preceding ejaculation. These results suggest that lumbosacral cord dopamine receptors may normally regulate male sexual performance.
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  • 89
    ISSN: 1432-2072
    Keywords: Riluzole ; FG 7142 ; β-Carboline ; Anxiety ; Conflict procedures ; Animal model ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The possible anxiolytic activity of riluzole, a drug which interferes with glutamic acid neurotransmission, was studied in rats using operant conflict procedures. In both “anxiolytic” and “anxiogenic” procedures, riluzole alone did not possess any anticonflict or proconflict effect at doses of 2 and 4 mg/kg PO. Riluzole over the same dose-range was able to antagonize the well known proconflict effect of the β-carboline derivative FG 7142, an inverse agonist at the GABA-benzodiazepine-chloride ionophore receptor complex. This effect could be related to the possible interaction of riluzole with glutamic acid neurotransmission, since it has been demonstrated previously that β-carbolines such as DMCM and β-CCM were able to deplete the levels of aspartic and glutamic acids in rodent cortex, perhaps by enhancing release of amino acid neurotransmitters. If one subscribes to the hypothesis that the anxiety induced by β-carboline derivatives is related to depression, riluzole might be of value in the treatment of anxiety related to depression.
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  • 90
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    Sexual plant reproduction 2 (1989), S. 154-166 
    ISSN: 1432-2145
    Keywords: Helianthus annuus ; Unfertilized ovule culture ; Parthenogenesis ; Ultrastructure ; Proembryo
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Electron microscope studies have been conducted on the parthenogenesis induced by in vitro culture of unfertilized ovules of sunflower (Helianthus annuus). In comparison with the state of the egg prior to inoculation, some eggs 5 days after culture show striking ultrastructural changes, which include, among others, nuclear migration, an increase in the number and activity of the organelles, a loss of polarity and wall formation at the chalazal end of the cell. Most of these changes are similar to those that occur normally in the zygote, indicating that parthenogenic development has been triggered in these eggs. Such eggs have been termed activated and are presumed to be capable of undergoing parthenogenesis. The parthenogenic proembryos which result share some features in common with zygotic proembryos. In addition, some parthenogenic proembryos exhibit unique properties not found in zygotic proembryos. These include embryos that consist of two parts differing markedly in density, an inversion of polarity, the frequent occurrence of autophagic vacuoles, the thickening of cell walls, a centripetal growth mode of wall formation, the appearance of an incomplete cell wall, free nuclear division, amitosis and degeneration. We believe that these ultrastructural peculiarities are the effects of in vitro culture.
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  • 91
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    Sexual plant reproduction 2 (1989), S. 193-198 
    ISSN: 1432-2145
    Keywords: Polymorphism ; Ultrastructure ; Pollen grains ; Canna indica L ; Tannin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Our investigations on Canna indica L. indicate that the pollen of this species is polymorphic: there are two types of pollen — a larger type and a comparatively smaller type. Transmission electron microscopy (TEM) revealed the presence of small vacuoles containing tannic substances in the generative cell (GC) of the larger grains: the GC of the mature grain contained a higher quantity of tannins than the GC of the immature grain. Mitochondria, lipid bodies, rough endoplasmic reticulum (RER) and microtubular bundles were present in the cytoplasm of the GC. Numerous mitochondria, lipid bodies and plastids were also present in the vegetative cell (VC), with the mitochondria clustered around the vegetative nucleus. The plastids were observed to be associated with the RER cisterns. During the maturation process, the number of starch grains contained in the plastids decreased.
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  • 92
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    Psychopharmacology 97 (1989), S. 175-178 
    ISSN: 1432-2072
    Keywords: Serotonin ; Morphine ; Nicotine ; Amphetamine ; Reward ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The effect of two potent and specific antagonists of 5HT3 receptors, ICS 205-930 and MDL 72222, on the reinforcing properties of amphetamine, morphine and nicotine was studied in rats. Durg-induced reinforcement was assessed by measuring drug-conditioned place preference. ICS 205-930 and MDL 72222 dose-dependently reduced the place preference induced by morphine (1.0 mg/kg SC). At doses of 0.030 mg/kg SC the two antagonists completely blocked morphine-induced place preference while doses of 0.015 mg/kg SC significantly reduced it. ICS 205-930 and MDL 72222 at doses of 0.030 mg/kg SC also prevented the place preference induced by nicotine (0.6 mg/kg SC). In contrast, ICS 205-930 and MDL 72222 up to doses of 0.030 mg/kg SC failed to modify the place preference elicited by amphetamine (1.0 mg/kg SC). The results indicate that 5HT3 receptors are specifically involved in the reinforcing properties of morphine and nicotine.
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  • 93
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    Psychopharmacology 97 (1989), S. 206-212 
    ISSN: 1432-2072
    Keywords: LSD-cue ; Drug discrimination ; Risperidone ; Schizophrenia ; 5-HT2-catecholamine antagonism ; LSD antagonism ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Risperidone was studied in a 0.16 mg/kg LSD-saline drug discrimination test procedure. At doses varying from 0.0025 to 0.63 mg/kg, no LSD-like agonist effects were observed. Studies on the antagonism of the LSD-cue indicated that risperidone was able to completely block the discriminative stimulus properties of LSD with a minimum ED50-value of 0.028 mg/kg. Risperidone was also very active over time with reference to LSD antagonism, the ED50s after 2, 4 and 8 h pretreatment being 0.028, 0.064 and 0.44 mg/kg. Response rate reductions were only observed at doses ≧0.16 mg/kg after 1 h and at 0.63 mg/kg after 2 h pretreatment. Four and 8 h after treatment, no rate-reducing effects were apparent at doses up to 2.50 mg/kg. Thus at pretreatment intervals ranging between 2 and 8 h, complete antagonism of LSD without any rate effects was obtained. As compared to other LSD antagonists, risperidone was quantitatively better than setoperone and ritanserin and longer acting than pirenperone. Based on the pharmacological profile of risperidone and the other LSD antagonists, it was concluded that a potent central 5-HT2 and catecholamine antagonism is needed for a potent and complete antagonism of the 0.16 mg/kg LSD-cue. The potential clinical effect of risperidone in the positive and negative symptoms of schizophrenia is discussed.
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  • 94
    ISSN: 1432-2072
    Keywords: Rat ; Operant behavior ; Fixed-interval ; Ventral tegmental area ; Neurotensin ; Substance P ; Neurokinin-α (substance K) ; d-Ala-Met-enkephalin ; Dopamine
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The neuropeptides neurotensin, substance P, neurokinin-α (substance K), and met-enkephalin are present endogenously in the ventral tegmental area (VTA), site of the A10 dopaminergic (DA) cell bodies. In the present study these four peptides were injected bilaterally into the VTA in the rat, and the effects on operant behavior were assessed. Cannulae aimed at the VTA were implanted in four groups of animals, which had been trained to bar-press for food reward on a fixed-interval, 40-s schedule. A fifth group, in which the effects of systemically administered amphetamine were assessed, was also tested. Response rate across the interval was measured, and the index of quarter-life was taken as an indication of the temporal pattern of resonding. In addition, a rate-dependency analysis was carried out for all data. Neurotensin (NT, 0.0175, 0.175, 0.5 μg in 1 μl) dose-dependently decreased response rates without affecting quarter-life, and reduced the number of reinforcements obtained. Substance P (SP, 0.1, 1.0, 3.0 μg) did not affect responding, and neurokinin-α (NKA, 0.1, 1.0, 3.0 μg) induced a small increase in responding. Quarter-life was not affected by SP or NKA, but responding on the nonreinforced lever was significantly increased by both peptides. d-Ala-met-enkephalin (DALA, 0.01, 0.1, 1.0 μg) induced a dose-dependent increase in responding which was also rate-dependent, and reduced quarter-life. DALA effects were similar to the classic pattern of responding observed after systemic amphetamine. These results suggest that although all these peptides elicit behavioral activation and may affect DA neuronal activity, the behavioral responses can be differentiated with respect to operant behavior.
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  • 95
    ISSN: 1432-2072
    Keywords: Sleep ; 5-Hydroxytryptamine (5-HT) ; Antagonist ; Agonist ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Recently developed agents specifically acting on different 5-hydroxytryptamine (5-HT) receptor populations were used to analyze the functional role of 5-HT2 receptor subtypes in the sleep-wakefulness cycle of the rat. The 5-HT2 receptor antagonist ritanserin injected intraperitoneally (IP) (0.04–2.5 mg/kg) induced an increase in deep slow wave sleep (SWS2) duration at the expense of wakefulness (W), light slow wave sleep (SWS1) and paradoxical sleep (PS). The stimulation of 5-HT2 receptors by 1-(2,5-dimethoxy-4-methylphenyl)-2-aminopropane (DOM) produced a dose-related increase in W and a dose-dependent decrease in both SWS2 and PS. Pretreatment with ritanserin (0.16–2.5 mg/kg) or with cinanserin (2.5–5 mg/kg), another 5-HT2 receptor antagonist, dose-dependently reversed the W enhancement and the SWS2 deficit produced by DOM, but not the PS deficit. Sleep-wakefulness alterations (increase in W and SWS1 combined with a suppression of SWS2 and PS) observed after IP injection of two putative 5-HT1 receptor agonists, 8-hydroxy-2-(di-n-propylamino) tetralin (8-OH-DPAT) (2.5 mg/kg) and 5-methoxy-3-(1,2,3,6-tetrahydro-4-pyridinyl)-1H-indole (RU 24969) (0.63 mg/kg), were not modified by ritanserin pretreatment (0.16–2.5 mg/kg). These results further support the hypothesis that the serotonergic system plays an active role in the regulation of the sleep-wakefulness cycle in the rat and that 5-HT2 receptors are involved in this action. In addition it is suggested that 5-HT1 receptor subtypes are unlikely to interact with 5-HT2 receptors in the sleep-wakefulness modulation mediated through 5-HT2 receptors.
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  • 96
    ISSN: 1432-2072
    Keywords: Amygdala ; Benzodiazepine ; GABA ; Barbiturates ; Conflict ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract In order to elucidate the role of the amygdala in rat conflict behavior in a water lick suppression test, we examined the effect of lesions of various nuclei of the amygdaloid complex on this behavior. An anticonflict effect was produced by a lesion of the anterior part of central and basolateral amygdala, and lesion to the posterior part of the central amygdala, but not by posterior of the basolateral amygdala or medial amygdala lesions. These results suggest that the amygdala, especially the anterior part of the central and basolateral nuclei, plays an important role in conflict behavior of rats in the water lick test. In a second experiment, the effects of benzodiazepine- and GABA-antagonists on the anticonflict action of diazepam, zopiclone, and phenobarbital injected into the anterior part of central and basolateral amygdala were examined, also using a water lick suppression test. A dose-dependent anticonflict action was produced by systemic administration as well as by intra-amygdala injection of diazepam, zopiclone, lormetazepam, flurazepam and phenobarbital. The order of potency was lormetazepam〉zopiclone≧diazepam〉flurazepam ≧phenobarbital for both routes of injection. The antiamygdala effects of diazepam and zopiclone injected into the amygdala were completely reversed by Ro15-1788 and β-CCM but not by bicuculline, while the anticonflict effect of phenobarbital was reversed by β-CCM but not by Ro15-1788 or bicuculline. The present results strongly suggest that the anterior nuclei of central and basolateral amygdala are important sites of action of antianxiety drugs, and that an anticonflict action produced by intra-amygdala injection of benzodiazepines or barbiturate is mediated through the different receptor mechansims.
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  • 97
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    Psychopharmacology 98 (1989), S. 61-67 
    ISSN: 1432-2072
    Keywords: Rat ; Place preference ; Extinction ; Conditioning ; Naloxone ; Heroin ; Clonidine ; Pimozide ; Memory
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract These experiments examined the neurochemical mechanisms involved in the development and expression of place conditioning produced by heroin. Conditioned place preferences (CPP) lasting up to 8 weeks were obtained with doses of 50–1000 μg/kg heroin, using a regimen shown not to produce physical dependence. Naloxone pretreatment (50 μg/kg) during conditioning prevented the acquisition of heroin-induced CPP, but when given only on the test day, naloxone (50 or 1000 μg/kg) did not prevent the expression of heroin CPP. Clonidine disrupted the establishment of heroin CPP at 20 μg/kg, but disrupted its expression only at debilitating doses (100 and 200 μg/kg). Pimozide attenuated the acquisition (100 μ/kg) and expression (250 μg/kg) of heroin CPP. Together, these results support a role for opioid and catecholamine systems in the acquisition of heroin reinforcement, but they suggest that once heroin CPP is established, its expression in opiate-free subjects is not opiate receptor mediated and is relatively refractory to pharmacological treatments which disrupt acquisition. The data challenge the notion that the conditioned effects of opiates in drug-free animals are related to the release of endogenous opioids, and they also may help to explain why naloxone and clonidine are ineffective in the treatment of opiate addiction.
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  • 98
    ISSN: 1432-2072
    Keywords: LY 163502 ; Dopamine D-1 and D-2 receptors ; Jerking ; Behavioural assessment ; Stereotypy ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The new, extremely potent and enantioselective D-2 agonist LY 163502 failed to induce compulsive stereotyped behaviour. Very low doses (3–6 μg/kg) inhibited spontaneous sniffing and locomotion, while higher doses (12–50 μg/kg) induced episodes of non-stereotyped sniffing and chewing; these actions showed complete enantioselectivity. Up to 200-fold higher doses modestly induced only locomotion. Responsivity to LY 163502 was enantioselectively blocked by the selective D-2 antagonist R-piquindone. This responsivity was also enantioselectively blocked by the selective D-1 antagonist R-SK&F 83566 but, additionally, episodes of atypical limb/body jerking behaviour were released; thus, LY 163502 induced such jerking only when tonic D-1 activity was suppressed. These data extend our notion that there may be at least two forms of functional interaction between D-1 and D-2 receptor systems: one cooperative, as in the regulation of typical sniffing, and another oppositional, as in the regulation of atypical jerking.
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  • 99
    ISSN: 1432-2072
    Keywords: Hallucinogenics ; Amphetamine ; Rat ; Tele-Stereo-EEG
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Telemetric recordings of field potentials from frontal cortex, hippocampus, striatum and reticular formation of freely moving rats were analysed before and after injection of the enantiomeric hallucinogenic amphetamine derivatives R-DOB [(−)-1-(2,5-dimethoxy-4-bromophenyl)-2-aminopropane], R-DOM [(−)-1-(2,5-dimethoxy-4-methylphenyl)-2-amino-propane] and R-DOI [(−)-1-(2,5-dimethoxy-4-iodophenyl)-2-aminopropanel] as well as the nonhallucinogenic amphetamine derivatives S-MBDB [(+)-N-methyl-1-(1,3-benzodioxol-5-yl)butanamine] and S-MDMA [(+)-3,4-methylenedioxymethamphetamine] and S-(+)-amphetamine. The frequency analysis of the field potentials revealed a clearcut difference between them. The spectral patterns emerging after injection of the non-hallucinogens were characterized by a general decrease of power, the changes in the alpha2 and delta band being the most prominent, whereas only after the application of the hallucinogenic compounds was a contrasting increase of power observed in the alpha1 frequency band, especially in the striatum. As increases in alpha1 power have been correlated in the same pharmacological model to serotonergic control mechanisms, the results are in line with the hypothesis that 5-HT2 receptors, predominantly occurring in the striatum, might be involved in the hallucinogenic action of drugs.
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  • 100
    ISSN: 1432-2072
    Keywords: Haloperidol ; Dopamine ; Oral movements ; Rat ; Tardive dyskinesia ; Homovanillic acid
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Rats with more severe orofacial movements after 51 days of haloperidol administration showed lower levels of the dopamine metabolite homovanillic acid (HVA) in the caudate compared to animals who did not develop significant mouth movements. This effect was not observed in other brain regions sampled. This finding is consistent with the hypothesis that dopaminergic receptor supersensitivity in neostriatal structures plays some role in the development of orofacial movements in rats, in association with chronic neuroleptic administration.
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