摘要:

AbstractWe have raised a monoclonal antibody (MAB‐1E10) reactive with the intact forms but not the processing products of the chromaffin cell vesicle protein chromogranin B (CgB). The antibody recognizes rat and human, but not bovine and chick adrenal chromaffin cells. In addition, MAB‐1E10 immunoreactivity was detected in rat PC 12 pheochromocytoma cells and in pituitaries. Several other tissues, including pancreas, small intestine and superior cervical ganglia, which are known to contain CgB in endocrine cells or neurons, respectively, were found not to be reactive with MAB‐1E10. Using short‐term cultures of dissociated adrenal chromaffin cells from Hannover‐Wistar rats, we found that the expression of intact CgB is developmentally regulated. Between embryonic day 19 and postnatal day 40, about 80% of adrenal chromaffin cells — identified by their reactivity with an antibody against the enzyme dopamine‐β‐hydroxylase — were found to be reactive with MAB‐1E10. The proportion of positive cells subsequently decreased to about 5% at postnatal day 90. In the presence of glucocorticoids, this decrease was reduced to about 45% CgB‐positive cells at postnatal day 90. In another rat strain, Sprague‐Dawley rats, the proportion of MAB‐1E10‐immunoreactive chromaffin cells (about 50%) remained constant from birth to adulthood. Our results indicate that CgB is differentially expressed and/or processed in different rat tissues, strains and during development, and furthermore, that expression or processing in rat chromaffin cells might be regulated by glucocorticoids. Intact CgB appears to be a marker for a subpopulation of chromaffin cells, but its function(s) remains to be clarified.

ISSN:0736-5748    

DOI:10.1016/0736-5748(92)90058-8

出版商:Wiley    

年代:2003

数据来源: WILEY

摘要:

AbstractThis study evaluated the effects of a combined gestational and 10 day postnatal alcohol exposure (human three trimester equivalency) on the development of glial cells in the rat optic nerve. Pregnant rats were exposed to alcohol via a liquid diet, then their pups were artificially reared and further exposed to alcohol for 10 postnatal days via a gastrostomy fed liquid diet. Control animals, born of pair fed dams, were artificially reared on pair fed isocaloric diets. Optic nerve tissues were prepared for light and electron microscopic studies from animals on gestational days (G) 15 and 20 and postnatal days (P) 5, 10, 15, 20 and 90. There were fewer glial cells per cross‐section on day 15 and the crosssectional areas of optic nerves were smaller on days G20, P15 and P90 in the ethanol exposed animals. There was an alcohol‐induced delay in the appearance of immature cells within the oligodendroglia lineage and a decrease in the number of oligodendroglia present at 15 and 20 days, indicating a delay in the maturation of oligodendroglial cells. These effects were compensated for by 90 days. Maturation of the astrocytic cell lineage was generally unaffected by the alcohol although there was evidence of increased numbers of cells in the lineage. There was no consistent indication of alcohol‐induced degeneration of glial cells or their organelles. Thus, alcohol exposure for all of gestation and 10 postnatal days in the rat causes a delay in oligodendrocyte maturation but appears to have no long‐term effects on the glial cell population of the optic nerve. Such a delay, by contributing to delays in myelin development, could help to explain some of the neurological dysfunctions associated with developmental alcohol exposures.

ISSN:0736-5748    

DOI:10.1016/0736-5748(92)90059-9

出版商:Wiley    

年代:2003

数据来源: WILEY

摘要:

AbstractAcetyl‐l‐carnitine produces a significant increase in the survival time‐course of adult rat sensory neurons maintained in primary cultures up to 40 days. The analysis of our data suggests that 200 μm acetyl‐l‐carnitine added to the medium, slows down neuronal decay especially in the first 10 daysin vitro, sparing a fraction of cells which would otherwise be lost.Patch‐clamp recordings from these neurons show that superfusion with acetyl‐l‐carnitine (100–1000 μM) does not induce any membrane current. In addition an agonist muscarinic effect particularly concerning high‐voltage activated calcium channel modulation appears to be ruled out.In conclusion our data favour the role of acetyl‐l‐carnitine in the trophism of sensory neurons in adult rats. In agreement with otherin vivoexperiments our data reinforce the hypothesis that this substance might be involved in reducing neuronal loss observed in nervous system aging.

ISSN:0736-5748    

DOI:10.1016/0736-5748(92)90060-D

出版商:Wiley    

年代:2003

数据来源: WILEY

摘要:

AbstractThe present study was conducted to investigate the qualitative and quantitative development of synaptic bodies in retinae of Wistar rats during postnatal days 4–28. In addition, the effects of different light regimens and of eye pigmentation on SB numbers were studied. Synaptic bodies were counted and measured in the outer plexiform layer of retinal tissue fixed and processed by routine electron microscopical techniques.At postnatal days 4 and 5, retinae showed only few synaptic bodies. The main numerical development of synaptic bodies occurred between postnatal days 4 and 9, numbers remaining more or less constant thereafter. The intracellular location of synaptic ribbons changed from predominantly cytoplasmic sites to positions at the membrane. In Wistar rats of postnatal day 15 held under a light/dark regimen, synaptic ribbon numbers and lengths were found to be significantly larger at night than at daytime. This was not observed in animals kept under constant darkness. In retinae of a pigmented rat strain, Brown Norway, total numbers of synaptic bodies were similar to those of Wistar rats, whereas the relative proportions of synaptic ribbons and spheres or sphere‐like structures, respectively, differed between strains. These results are discussed with regard to synaptic body formation and regulation under the influence of light and eye pigmentation.

ISSN:0736-5748    

DOI:10.1016/0736-5748(92)90061-4

出版商:Wiley    

年代:2003

数据来源: WILEY

摘要:

AbstractInhibitors of gamma‐glutamyl transpeptidase (mixture of serine and borate — 13 mM, kainic acid — 5 mM and 6‐diazo‐5‐oxo‐L‐norleucine — 2 mM) significantly suppressed glutamate uptake into cultured neurones and glial cells. The simultaneous application of any of these inhibitors with ouabain resulted in a further decline in glutamate uptake. It can be speculated that gamma‐glutamyl transpeptidase significantly contributes to glutamate transport into nerve cells in the early period of brain development until the Na+‐K+‐gradient is fully constituted.

ISSN:0736-5748    

DOI:10.1016/0736-5748(92)90062-5

出版商:Wiley    

年代:2003

数据来源: WILEY

摘要:

AbstractThe possibility of a direct infection of human brain by HTLV‐I, has been studied using anin vitromodel. Human fetal astroglial cells were cocultivated with irradiated HTLV‐I donor cell line MT‐2, and assayed for the presence of HTLV‐I core protein p19 after 1 week. Fifty‐six per cent of GFAP positive astrocytes showed the viral core protein p19 and increased expression of Class II MHC antigens. Electron microscopy of astroglial cells exposed to HTLV‐I revealed the presence of vacuoli‐like structures containing viral core protein p19. Cell intermediate filament cytoskeleton was also disorganized. Even if this study does not provide direct evidence for virus replication inside astroglial cells, all these findings suggest that HTLV‐I can indeed enter the cell and exert a cytopathic effect. Therefore the results of the present study are consistent with the hypothesis that astroglial cells could be involved in demyelination processes occurring in the HTLV‐I associated neurological disorders, such as human associated myelopathy and tropical spastic paraparesis.

ISSN:0736-5748    

DOI:10.1016/0736-5748(92)90063-6

出版商:Wiley    

年代:2003

数据来源: WILEY

ISSN:0736-5748    

DOI:10.1016/0736-5748(92)90064-7

出版商:Wiley    

年代:2003

数据来源: WILEY