摘要:

AbstractExpression of intercellular adhesion molecule‐1 (ICAM‐1), ICAM‐2‐like molecule (Lgp55), and class I/II major histocompatibility complex (MHC) antigens (H‐2 and Ia) was investigated in cultures of mu‐rine Oligodendrocytes and astrocytes. Under unstim‐ulated conditions, low levels of ICAM‐1 expression were observed on astrocytes (95%), while Ia antigen induction was low on astrocytes (<50%) and did not occur on Oligodendrocytes. Cell type‐specific expression and induction of ICAMs and MHC antigens by immune mediators may play roles in lymphocyte‐glial cell interactions at the sites of inflammat

ISSN:0360-4012    

DOI:10.1002/jnr.490290102

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

年代:1991

数据来源: WILEY

摘要:

AbstractFunctional properties of ramified microglia were investigated in primary cultures of rat cerebral cortical celts. These microglia could be readily identified in both fixed and living cultures through previously established features. Based on their destruction by 5 mM L‐leucine methyl ester, a high level of intrinsic endocytotic activity was established. When cultures were incubated with fluorescent latex beads to assess phagocytosis, little or no such activity was exhibited by ramified cells. However, when cultures were incubated with dyes or other soluble tracer compounds, these cells always exhibited labeling. This labeling was selective for ramified microglia in the cultures and was demonstrated using a variety of compounds, including trypan blue, lucifer yellow, horseradish peroxidase (HRP), and India ink. Intracellular label could be observed in vesicular structures; this localization corresponded to an active cellular process. Also, cellular labeling was inhibited by the presence of colchicine. These features supported the inference that the labeling was attributable to pinocytosis, and this process appeared to account for the vast majority of endocytotic activity in the ramified microglia. Possible physiological significance of this pinocytotic activity was indicated by the accumulation of various neurotransmitters/modulators: γ‐aminobutyric acid and vasoactive intestinal polypeptide (VIP). Ramified cells in these cultures have been previously noted to exhibit a constant and rapid pattern of motility, which was consistently observed here through time‐lapse video recording; pinocytosis and rapid motility were shown to concur in individual cells. Based on their high intrinsic pinocytotic activity and pattern of cellular motility, the ramified microglia specifically are suggested to serve a constitutive function of fluid cleansing within the interstitial spaces of brain

ISSN:0360-4012    

DOI:10.1002/jnr.490290103

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

年代:1991

数据来源: WILEY

摘要:

AbstractWe compared the effect of two neuropeptides, calcitonin generelated peptide (CGRP) and vasoactive intestinal peptide (VIP), on mitogen‐induced murine splenocyte proliferation. Both neuropeptides exerted their maximal effect within 24 hr after activation by Con A. The combination CGRP‐VIP caused an additive inhibitory effect on T‐cell proliferation. The inhibitory effect of VIP could be correlated with a decrease in interleukin 2 (IL‐2) production, whereas CGRP did not affect this production. Since we also observed an additive inhibitory effect on T‐cell proliferation by the theophylline and CGRP or VIP combination, we measured the effect of each neuropepntide on intracellular cAMP production by enriched T‐cells: CGRP, but not VIP, strongly stimulated cAMP synthesis. Taken together, our results indicate that inhibition of murine T‐cell proliferation by CGRP and VIP is mediated by differe

ISSN:0360-4012    

DOI:10.1002/jnr.490290104

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

年代:1991

数据来源: WILEY

摘要:

AbstractThis study aimed at analyzing the regulation of in vitro serotonin expression by neurons taken from different regions of the embryonic rat rhombenceph‐alon. We studied the influence of co‐culture with alar‐plate tissue using immunocytochemical and biochemical methods.Computer‐assisted densitometry was used to estimate the co‐culture effects on the serotonin content of the cell bodies. The more dynamic aspects of serotonin expression, such as synthesis and release, were studied by measuring (3H)serotonin newly synthe‐sized from (3H) tryptophan.The density of the immunostaining was significantly decreased in B1, B2 cells by co‐culture with both caudal and rostral alar‐plate tissue. For B4–B9 cells, only co‐culture with rostral alar‐plate tissue produced a significant decrease. The de novo synthesis of serotonin was significantly decreased in B1, B2 neurons co‐cultured with caudal alar‐plate tissue only. Once again, the B4–B9 cells proved to be less influenced by the experimental conditions, as co‐culture with both types of alar‐plate tissue produced no significant effect.We concluded that the in vitro expression of serotonin can be modulated by environmental factors, but the relative influence of these factors is very different in rostral versus caudal seroto

ISSN:0360-4012    

DOI:10.1002/jnr.490290105

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

年代:1991

数据来源: WILEY

摘要:

AbstractTo find out if in vitro maintenance produces changes in the electron microscopic appearance, protein composition, and phosphorylation properties of guinea pig CNS myelin fractions, we incubated them for 10 min, 4 hr, 24 hr, and 48 hr in phosphate‐buffered saline (pH 7.4) or in 20 mM Hepes, 2 mM EDTA, 0.5 mM EGTA, 0.5 mM dithiothreitol, and 20 mM NaCl at 4 and 30°C. Aliquots were processed for electron microscopic study, were analyzed for protein content by gel electrophoresis, and were assayed for endogenous protein phosphorylation. Before incubation, electron micrographs of fractions contained two types of multilamellar whorls with the periodicity of CNS myeiin sheaths. The first type of whorl was separated from nearby whorls; the other type had surface lamellae that were connected to other multilayered membrane fragments. After incubation at 4°C for 24 hr, the number of both types of multilamellar whorls in micrographs had increased approximately 3‐ to 4‐fold. Counts per unit area showed that the observed increase was both time‐ and temperature‐dependent. In aliquots studied by gel elect, ophoresis, only minor degradation of myeiin proteins was observed. The endogenous protein phosphorylation properties of the myeiin fragments also remained functional, suggesting that the activities of protein phosphotransferases were not altered. We conclude that the incubation conditions described here favor interactions of proteins and lipids that lead to the formation of multi‐layered aggregates of CNS mye

ISSN:0360-4012    

DOI:10.1002/jnr.490290106

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

年代:1991

数据来源: WILEY

摘要:

AbstractThe long‐chain fatty alcohol, n‐hexacosanol, has been shown to possess neurotrophic properties in vitro on rat CNS cultures (Borg et al., 1987) and to promote the survival of septal cholinergic neurons after experimental axotomy (Borg et al., 1990). Long‐chain alcohols have also been shown to be synthesized and metabolised by rat brain during development (Bishop and Hayra, 1981; Natarajan et al., 1984). The present study was undertaken in order to find out if a nonproteic neurotrophic factor like n‐hexacosanol may be able to reduce the neuronal damages induced by the excitatory amino acid, kainic acid. When administered chronically by intraperitoneal injection, hexacosanol (1 mg/kg) protected the pyramidal neurons of the hippocampus from the neurotoxic degeneration induced by an intracerebroventricular infusion of kainic acid in rats; the extent of the damage was limited to a small part of the CA3 region. Mor‐phometric analysis showed that 72% of the neurons that would have died following kainic acid injection were spared by hexacosanol. Moreover the increased locomotor activity induced by the neurotoxin was also inhibited by hexacosanol and the behavioral effect was statistically correlated to the extent of neuronal loss. The present study suggests a possible role for nonproteic neurotrophic compounds against neurotoxic damages on central neurons. Moreover the peripheral administration of hexacosanol may lead to a significant breakthrough in the treatment of excito‐toxin‐related h

ISSN:0360-4012    

DOI:10.1002/jnr.490290107

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

年代:1991

数据来源: WILEY

摘要:

AbstractUsing computerised densitometry to measure immunocytochemical reaction product in a model system, we established conditions that produced a linear relationship between the logarithm of antigen concentration and the measured intensity of staining. We then applied the densitometric technique to assess the changes in tyrosine hydroxylase (TH) and neuropep‐tide tyrosine (NPY) within sympathetic neurons of rat superior cervical ganglion following chronic decentralization and following reserpine treatment. One week after surgical or pharmacological decentralization, there was appreciable reduction of neuronal levels of both TH and NPY. However, there remained considerable variation in the immunoreactivities of individual cells. Three days of treatment with reserpine elevated TH levels but substantially reduced NPY. Both these effects were prevented by prior decentralization of the ganglia. No differences were seen between normotensive and the Otago strain of genetically hypertensive rats, either in basal TH or NPY immunoreactivities or in responses to the maneouvres performed. Comparison of our findings with previous biochemical data indicate that densitometric immunocytochemistry provides an accurate index of neuronally localised antigen concentrations but also allows analysis of interneuronal differences that are not otherwise apparen

ISSN:0360-4012    

DOI:10.1002/jnr.490290108

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

年代:1991

数据来源: WILEY

摘要:

AbstractA novel approach was developed to raise a panel of monoclonal antibodies (mAb) against brain antigens usingXenopusoocytes as immunological vectors.Xenopusoocytes were injected to express proteins encoded by brain‐derived mRNA extracted from rat cerebral cortex. A crude membrane preparation from mRNA‐injected oocytes was then used to immunize mice previously rendered immunotolerant to native oocyte membranes. mAb reacting with cryostat cut sections from rat brain were selected and further characterized by immunohistological and immunobiochemical techniques. Several mAb recognized brain specific antigens, including some that were cell type specific and others that revealed a regional binding pattern. A particular group of antibodies recognized an epitope localized exclusively to the cerebellar pinceau terminals. Although some of the hybridomas found in this panel may be products of natural autoreactive lymphocytes, the presence of a specific immune response to mRNA expression products is discussed. These results indicate that mRNA injected oocytes are useful tools to raise mAb to study the molecular diversity of the nervous sys

ISSN:0360-4012    

DOI:10.1002/jnr.490290109

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

年代:1991

数据来源: WILEY

摘要:

AbstractThe proportion of cultured rat oligodendrocytes (OL) that extended processes of over three soma diameter in length is dependent on the age of the animals from which the brains were derived; up to 70% of neonatal OL attained this criterion within 3 days, and this proportion progressively decreased with advancing ages of the animals (1, 3, and 6 months). The lower extent of process formation from older rat OL could he augmented, and indeed to equal neonatal levels, by treatment of cells with phorbol esters that stimulate protein kinase C: 4β‐phorbol‐12,13‐dibutyrate (PDB) and phorbol‐12‐myristate‐13‐acetate (PMA). Enhancement of process formation, by PDB and PMA was also observed for cultured adult human and bovine OL. For adult OL from all three species, a phorbol ester that binds but that does not activate protein kinase C, 4α‐phorbol‐12,13‐didecanoate, did not result in enhancement of process formation. Selectively to biologically active phorbol esters was shown by the inability of a wide range of growth factors to promote process extension. Immunohistochemical analyses indicate that the type III isozyme of protein kinase C predominates in cultured OL; the apparent intensity of immunoreactive PKC was not different between controls or cultures treated for 12 days with PDB, suggesting that the persistent presence of PDB might not have down‐regulated the enzyme, in contrast to other cell types. We propose that stimulation of protein kinase C is critical to the triggering of process formation

ISSN:0360-4012    

DOI:10.1002/jnr.490290110

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

年代:1991

数据来源: WILEY

摘要:

AbstractThe cytotoxic effects of oxygen radicals have been studied in enriched population of mature bovine oligodendrocytes in culture. Oxygen radicals were generated enzymatically by glucose and glucose oxidase, and hypoxanthine and xanthine oxidase combinations. Cytotoxicity was assessed by trypan blue exclusion and percentage lactate dehydrogenase release into the culture media. Incubation of bovine oligodendrocytes with these oxygen radical‐generating systems for 4 hr resulted in significant cell death, especially in the glucose oxidase system. The oligodendrocytes were completely protected by catalase from the cytotoxic effects of both oxygen radical generating systems. However, superoxide dismutase, dimethylsulfoxide and antioxidants such as vitamin E and glutathione did not protect oligodendrocytes from the oxidant‐mediated cytotoxicity. It appears that hydrogen peroxide produced in these oxygen radical‐generating systems gives rise to toxic radicals that induce the cell death of bovine oligodendrocytes in cu

ISSN:0360-4012    

DOI:10.1002/jnr.490290111

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

年代:1991

数据来源: WILEY