摘要:

AbstractExternal application of bradykinin (BK) to mouse neuroblastoma × mouse fibroblast hybrid NL308 cells and mouse neuroblastoma × rat glioma hybrid NG108–15 cells produced a transient outward (hyperpolarizing) current. In NG108–15 cells, BK also induced an inward (depolarizing) current associated with a decrease in input membrane conductance, which results from the inhibition of a voltage‐sensitive potassium current, the M‐current. However, in NL308 cells, either no depolarization was elicited by BK or, even if the BK‐induced depolarization was evoked, it was associated with an increased conductance. To explain the above difference, the intracellular second messenger system of NL308 cells was examined in detail. BK induced the rapid accumulation (three‐ to fivefold higher than the control level) of inositol 1,4,5‐trisphosphate (InsP3) in NL308 cells. The cytosolic Ca2+concentration was also elevated to 540 nM from 180 nM at a basal level. This seems to be enough to activate a voltage‐independent and Ca2+‐sensitive K+current, resulting in the hyperpolarization. Intracellular injection of InsP3replicated the hyperpolarization. NL308 cells possess protein kinase C (C‐kinase), with specific activities of C‐kinase in cytosolic and membrane fractions being 233 and 24 pmol/min/mg protein, respectively. The activity associated with particulates became higher after phorbol dibutyrate (PDBu) treatment. But NL308 cells did not show the characteristic inward relaxation by step hyperpolarizations and the outward rectification in the current‐voltage relationship, indicating that the M current is deficient in NL308 cells. Therefore, application of PDBu failed to mimic the inward current. The results suggest the role of InsP3and C‐kinase in

ISSN:0894-1491    

DOI:10.1002/glia.440030102

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1990

数据来源: WILEY

摘要:

AbstractA mouse monoclonal antibody to human chromogranin A (LK2H10) selectively stains the Bergmann glia (Golgi epithelial cells) of the rat cerebellum, while rabbit antibodies to bovine or porcine chromogranin A do not. Chromogranin A immunostaining in the cell bodies and processes reveals the characteristic candelabra morphology seen in Golgi preparations of these cells. Immunostaining adjacent sections with antibodies to glial fibrillary acidic protein shows that a relatively small number of the glial cell processes in the molecular layer are chromogranin A positive. Recent reports indicate that the metabolites of chromogranin A play a regulatory role in endocrine and neuroendocrine systems but the function of chromogranins in neurons and glia is unknown.

ISSN:0894-1491    

DOI:10.1002/glia.440030103

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1990

数据来源: WILEY

摘要:

AbstractAstrocytic glial fibrillary acidic protein (GFAP) immunoreactivity in response to retrograde changes of motoneurons after axotomy has been the subject of a number of reports. In contrast, this study examined the astrocytic GFAP immunoreactivity in response to axotomy in a sensory system, the adult rat olfactory system. The purpose of this study was to determine, by immunolabeling GFAP, the extent and transience of astrocytic reactivity in the olfactory system. Unilateral transection of the olfactory nerve fascicles was performed intracranially at the level of the cribriform plate. Rats were allowed to survive from 24 hours to 1 month after axotomy. GFAP immunolabeling was examined throughout the rat olfactory system using the peroxidase–anti‐peroxidase method. After axotomy, a transient increase occurred in the astrocytic GFAP immunore‐activity in the ipsilateral olfactory system. The greatest enhancement of GFAP immuno‐reactivity in the olfactory system occurred at 48 hours post‐axotomy. Increased GFAP immunoreactivity occurred not only along the axons and synaptic endings of the injured primary olfactory neurons, but also along the dendrites, cell bodies, axons, and synaptic endings of the secondary sensory neurons. The increased GFAP immunoreactivity was specifically associated with the anatomical distribution pathways of the primary and secondary olfactory neurons. Increased GFAP immunoreactivity was not altered until 14 days post‐axotomy. At 1 month post‐axotomy, GFAP immunoreactivity returned to control levels. The time course and transience of increased GFAP immunoreativity closely correlates with the time course of rat primary olfactory neuronal degeneration and regeneration after axotomy. The increase in astrocytic GFAP immunoreactivity along the secondary olfactory neurons suggests the existence of a transsynaptic effect that is directly related to the state of degeneration and regeneration of the primary olfa

ISSN:0894-1491    

DOI:10.1002/glia.440030104

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1990

数据来源: WILEY

摘要:

AbstractIn caprine β‐mannosidosis, an inherited dysmyelinating disorder, the myelin deficit shows substantial variation throughout the nervous system. In this study morphometric analysis of optic nerve and corpus callosum sections at selected developmental stages was conducted in order to investigate development and persistence of myelin sheaths, the population of axons ensheathed, and the extent of myelin deficits and glial cell abnormalities. The results show that the myelin deficit is severe at very early stages of development and persists to about the same extent into postnatal life. The corpus callosum, much more severely involved than the optic nerve, contains a substantially smaller percentage of myelinated axons when compared to control. In both regions, larger axons are preferentially myelinated. In the corpus callosum before myelination begins, many glial cells appear abnormal, suggesting an early cellular defect. In the postnatal, myelin‐deficient corpus callosum, there is a substantial decrease in glial cell density as compared to control, with abnormal appearance of many of the remaining cell profiles. These results define developmental characteristics of the dysmyelination in caprine β‐mannosidosis and document both the early appearance and the persistence of glial cell body and myelin abnorm

ISSN:0894-1491    

DOI:10.1002/glia.440030105

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1990

数据来源: WILEY

摘要:

AbstractBy using an antibody to goldfish glial fibrillary acidic protein (GFAP), the reaction of goldfish optic nerve to injury has been studied by immunoblotting and immunohistochemical methods. Goldfish optic nerve, which normally lacks GFAP immunoreactivity (Nona et al.:Glia, 2:189–200, 1989), expresses GFAP following injury. This immunoreactivity, which is observed as early as 10 days after crush and which is still evident at 30 days after crush, all but disappears by 150 days after crush. Since it is well established that functional restoration of synaptic connections and the recovery of vision takes place in goldfish following optic nerve injury, our results indicate that reactive astrocytes do not represent an impediment to regeneration in goldfish visual syste

ISSN:0894-1491    

DOI:10.1002/glia.440030106

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1990

数据来源: WILEY

摘要:

AbstractStimulation of guanylate cyclase in vitro by atrial natriuretic factor (ANF) or sodium nitroprusside was studied in rat brain tissue slices biochemically as well as by means of cyclic guanosine monophosphate (cGMP) immunocytochemistry. The ANF‐responsive, cGMP‐producing cells were studied in the olfactory bulb, the septal area, the hippocampus, the medial amygdala, and the medial preoptic area. These cells, having the ANF‐stimulated particulate guanylate cyclase, were characterized as astroglial cells on the basis of their glial fibrillary acidic protein (GFAP) immunostaining, although not all astroglial cells in these areas could be identified as cGMP‐immunoreactive cells. Sodium nitroprusside‐stimulated soluble guanylate cyclase activity was demonstrated in neuronal cell bodies and varicose fibers and was associated with blood vessel walls.Upon maturation, a significant decrease in cGMP production was found after stimulation by 100 nM ANF‐(103–126) in the olfactory bulb, the medial amygdala, and the hippocampus, but not in the septal area; no change was found in these areas in cGMP content after stimulation of cGMP production by 10 μM sodium nitroprusside. Via cGMP immunocytochemistry, no qualitative differences were seen in the ANF‐responsive, cGMP‐producing cel

ISSN:0894-1491    

DOI:10.1002/glia.440030107

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1990

数据来源: WILEY

摘要:

AbstractPrevious studies using dissociated cell cultures of fetal rat brain have revealed considerable regional diversity as well as sex steroid‐independent sex differences in developmental schedules of dopaminergic neurons. Because these phenomena might be related to glial heterogeneity, cultures of dissociated male and female diencephalon, mesencephalon, and rhombencephalon of gestational day 14 rats were investigated with respect to the development of astrocytic markers. Cultures were incubated for 3–8 days in vitro (DIV) in serum‐supplemented or serum‐free medium. Vimentin and glial fibrillary acidic protein (GFAP) were quantified by counting of immunolabeled cells and immunoblotting. Vimentin and GFAP content rose from DIV 3 to 6 in all cultures. Regional variation of vimentin content was low, but large differences occurred in amounts of GFAP. GFAP reached high levels in rhombencephalon, especially when supplemented with serum, but remained very low or not detectable in mesencephalon. Simultaneous immunostaining for both cytoskeletal proteins revealed the presence of large numbers of vimentin single‐labeled and small numbers of vimentin/GFAP double‐labeled cells. Numbers of cells expressing GFAP showed similar regional variations as GFAP contents in both serum‐free and serum‐supplemented medium. They rose steeply from DIV 3 to 8 in rhomb‐ and diencephalon but not in mesencephalon. Transiently, female diencephalic cultures contained slightly more GFAP‐immunoreactive cells than male cultures. The results thus demonstrate considerable regional heterogeneity of astrocytic maturation. However, neither the regional nor the sex differences show a consistent correlation with previous data on development of dopaminergic and other monoaminergic neurons in vitro. It seems likely that the dependence of neurons on glial environment for realization of an inherent developmental program varies among

ISSN:0894-1491    

DOI:10.1002/glia.440030108

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1990

数据来源: WILEY

摘要:

AbstractOligodendrocytes were isolated from the white matter of young trout by Percoll density centrifugation of enzymatically dissociated tissue and cultured on poly‐D‐lysine–coated petri dishes. Using antisera recognizing myelin‐specific compounds of fish CNS (36K, IP2) up to 72% of the isolated cells could be identified as oligodendrocytes with an average yield of 4 X 106cells per gram of wet tissue. Taken in culture, the cells rapidly regenerated their processes and soon acquired a morphology closely resembling mammalian oligodendrocytes in vitro. On the other hand, in terms of phenotypic expression, interesting parallels were revealed with the known in vitro behavior of Schwann cells: Galactocerebroside, which in mammalian oligodendrocytes is persistently expressed over longer periods of time in vitro, rapidly disappeared from the surface of cultured trout oligodendrocytes. In contrast, the fish CNS myelin glycoprotein IP2, which like IP1 is immunologically related to the major myelin product of Schwann cells, Po, was continuously expressed over several weeks in culture. Two other myelin protein constituents, 36K and IP1, transiently declined in vitro, but later on fully reappeared in the glial cells of trout. The present cell culture system offers an experimental model for studying in vitro the factors underlying oligodendroglial regeneration and remyelination in the f

ISSN:0894-1491    

DOI:10.1002/glia.440030109

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1990

数据来源: WILEY

摘要:

AbstractAstroglial cells from mouse cerebral hemispheres, cerebellum, olfactory bulbs, and medulla oblongata were grown in the presence of either hormones (hydrocortisone, insulin) or cell second messengers (dBcAMP, dBcGMP). Glutamine synthetase (GS) specific activity, GS protein level, and GS translation were investigated under the effect of these factors. Hydrocortisone produced a simultaneous increase in GS translation, GS level, and activity. This increase was observed in the astrocytes cultured from the four brain areas but at a variable magnitude depending on the area. The hydrocortisone effect appeared at the transcriptional level. Inversely, insulin decreased both the GS activity and the in vitro translated GS. This effect was seen only in the olfactory bulbs and the medulla. DBcAMP increased the GS biological activity only in the cerebral hemisphere cultures. It raised, however, the level of translated GS and GS protein in astrocytes from all the areas, suggesting a post‐translational effect for intracellular cAMP. DBcGMP only affected GS in the astrocytes from cerebral hemispheres and the medulla modulating either the GS transcription or the messenger RNA stability.These results suggest specific regulation for GS expression, depending on the brain area from which the cells were dissociated or on the astroglial cell population present in these cultures affecting either the transcription, the mRNA stability, or the biological activity of the protei

ISSN:0894-1491    

DOI:10.1002/glia.440030110

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1990

数据来源: WILEY

ISSN:0894-1491    

DOI:10.1002/glia.440030101

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1990

数据来源: WILEY