摘要:

AbstractSeptal neurons from embryonic rats do not survive for 24 hr when dissociated and cultured at low density in a serum‐free medium. Lamunin at 5–40 μg/ml acts as a survival‐promoting agent in the presence of 1 mM pyruvate. Laminin is effective in promoting survival only if it is added before or during cell plating; it does not support survival if added after cell attachment. Variations in laminin concentration do not effect the total number of cells attaching to the culture plate. The percentage of septal cells with neurites is increased in a dose‐dependent manner by laminin as early as 45 min after cell plating, suggesting an effect of laminin on the rate of neurite initiation. Neurite extension at 24 hr is also dependent on laminin concentration. This study suggests that some interaction between cells and the substrate, independent of cell attachment, has a profound effect on cell physiology, increasing both cell survival and the rate of neurite extension. This study also defines the survival requirements of septal neurons in a chemically defined environment in a low‐density situation where cellular interactions are at

ISSN:0360-4012    

DOI:10.1002/jnr.490150102

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

年代:1986

数据来源: WILEY

摘要:

AbstractA soluble, heat‐labile, trypson‐sensitive factor present in extracts of astrocyteenriched cultures enhances the expression of myelination‐associated events in rat brain cultures enriched in oligodendrocytes. Both the number of oligodendrocytes detected by immunofluorescence microscopy and the levels of biochemical activities associated with oligodendrocyte differentiation increased in the cultures in respose to the extract in a time‐ and concentration‐dependent fashion. The possible significance of these studies of normal oligodendrocytes function, and thus myelination, is

ISSN:0360-4012    

DOI:10.1002/jnr.490150103

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

年代:1986

数据来源: WILEY

摘要:

AbstractPrimary cultures of astrocytes free of neurons and containing less than 1% of oligodendrocytes were examined for their ability to incorporate labeled precursors into lipids and glycolipids. At selected developmental stages cultures were doublelabeled with either [3H]glycerol and [14C]acetate or with [3H]galactose and Na2[35SO4] for a total of 72 hr. Lipids were extracted with CHCl3/CH3OH, fractionated on a silicic acid column, and further resolved by two‐dimensional thin‐layer chromatography. It was found that (1) cultured astrocytes actively incorporate acetate and glycerol into various phospholipids; (2) they have very limited ability to utilize galactose and virtually lack the synthetic machinery to use Na2SO4for the synthesis of sulfated sphingogalactolipids; and (3) their overall lipid metabolism is very distinct from that of oligodendrocytes. It was also found that cultured astrocytes have low levels of 2′,3′ cyclic phosphodiesterase and glycerol phosphate dehydrogenase activities; the latter is less than one fifth of that in oligodend

ISSN:0360-4012    

DOI:10.1002/jnr.490150104

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

年代:1986

数据来源: WILEY

摘要:

AbstractThe mixed glial system of primary cultures of cells dissociated from neonatal rat brain was utilized to study glial differentiation. The investigation was addressed specifically to the possibility of noncoordinate regulation of two manifestations of oligodendroglial differentiation, i.e., activities of glycerol‐3‐phosphate dehydrogenase (GPDH) and of 2′,3′‐cyclic nucleotide 3′‐phosphohydrolase (CNP), as well as the effects of initial cell density on the time of onset and the intensity of expression of these aspects of oligodendroglial differentiation. Simultaneously, glutamine synthetase activity was studied to determine effects on astrocytic differentiation. GPDH exhibited a major developmental increase in specific activity between 20 and 32 days in culture. However, CNP activity exhibited a major developmental increase that commenced approximately 2 weeks earlier. The onset of these expressions of oligodendroglial differentiation was not affected by such environmental factors as initial cell density. However, the intensity of expression of the temporally separate increases in GPDH and CNP activities was markedly density‐dependent. The highest activities were attained in cultures plated at the lowest cell densities. The astrocytic enzyme, glutamine synthetase, also exhibited a striking developmental increase (approximately tenfold between 13 and 30 days in culture), but initial cell density affected neither the time of onset nor the intensity of expression of this aspect of astrocytic differentiation. The data demonstrate a striking developmental increase in GPDH activity that is not coordinate with that in CNP. The noncoordinate manifestations of oligodendroglial differentiation commence as a function of time in culture, whereas the intensity of expression of this differentiation can be influenced by such environmental factors as initial cell density. Neither the onset of nor the extent of the sharp increase in glutamine synthetase activity, an expression of astrocytic differentiation, is affected by initi

ISSN:0360-4012    

DOI:10.1002/jnr.490150105

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

年代:1986

数据来源: WILEY

摘要:

AbstractWe have prepared highly purified cultures of rat oligodendrocytes by a modification of the procedure of McCarthy and de Vellis [1980]. By utilizing a substratum derived from lysed glia and a calf serum‐containing medium with a high concentration of transferrin, the oligodendrocyte cultures display a high degree of purity, the ability to survive several months of culture, and a striking ability to produce a myelin‐like membrane. We have examined the production of this myelin‐like membrane using immunocytochemical and biochemical probes as well as an extensive morphological examination at the electron microscopic level. The membrane appears to be produced in a similar developmental pattern to that observed in vivo and it has the structural characteristics of loosely packed central nervous system m

ISSN:0360-4012    

DOI:10.1002/jnr.490150106

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

年代:1986

数据来源: WILEY

摘要:

AbstractPolylysine‐coated sepharose beads were implanted in the cerebellum of neonatal rats and examined at 3 hr, 3 days, 14 days, and 21 days after surgery. Previous studies at 5 or 8 days after implantation showed that axons formed neuronal swellings that appeared to be presynaptic elements, with the bead surface in the position of a postsynaptic element. Results reported here show that no beads at 3 hr had presynaptic elements, whereas the number of beads with presynaptic elements increased to high levels at 3 and 7 days but dropped to low values at 14 and 21 days after implantation. Presynaptic elements were seen on beads regard less of their distance from cerebellar tissue except at 3 hr, when no axons were seen in the implant, indicating that axons first grew into the implant and then formed presynaptic elements. The morphological measurements of presynaptic elements on beads at 3 to 7 days after implantation showed increases in area and number of synaptic vesicles, which then decreased at 14 and 21 days after implantation.These results show that axons can grow into implants of polylysine‐coated beads and form presynaptic elements that do not survive with increased time after implantation. The survival of presynaptic elements on beads can be used as a model for investigations into regeneration of axons and presynaptic elements in the injured br

ISSN:0360-4012    

DOI:10.1002/jnr.490150107

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

年代:1986

数据来源: WILEY

摘要:

AbstractGlial cell cultures derived from newbron and aged (18‐month‐old) mouse cerebral hemispheres and maintained up to cell passage 11 were characterized immunocytochemically by using glial fibrillary acidic protein (GFA), and biochemically by using glutamine synthetase (GS), for astrocytes, and 2′,3′ cyclic nucleotide 3′ phosphohydrolase (CNP) for oligodendrocytes. We report here the changes occurring during passages 5–1. GS and CNP activities did not significantly changes with cell passage in cultures from newbron mouse. In cultures derived from aged mouse, CNP activity did not change signigicantly whereas GS activity increased severalfod. A characteristic finging in higher cell passages (passage #7) was the loss of GFA‐positive stained cells and the appearance of multinucleated cells. We interpret these changes in culture to represent possible signs of cellul

ISSN:0360-4012    

DOI:10.1002/jnr.490150108

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

年代:1986

数据来源: WILEY

摘要:

AbstractIsolation of several of the charge isomers from both normal and multiple sclerosis (MS) myelin basic protein (MBP) was achieved on CM‐52 columns at pH 10.6. In liquid x‐ray diffraction and agregation experiments, corresponding charge isomers were equally effective in the formation of multilayers, demonstrating the dominant role of overall net positive charge. These studies demonstrated that the change in overall charge of MBP of one net positive charge was sufficient produce large changes in aggregation and in multilayer formation. The x‐ray diffraction experiments showed that component 1 was twice as effective as component 2 although they differed in charge by a single positive charge. Component 3 was less effective than component 2 and component “8” was not effective at all. Vesicle aggregation also showed a dependence on net positive charge. In order of decreasing effectiveness, component 1>component 2>component 3>component “8”.Since overall charge on MBP is determined by contributions from the various charge isomers, the relative proportions of these charge isomers favoring the less cationic components could explain the observation that MBP from MS victims was less effective than MBP form normal brain in vesicle aggregation and multilayer formation. The isolation of myelin‐containing white matter fractions from both normal and MS tissue in which the loss of some of the most cationic charge isomers was correlated with presence of less compact myelin supports

ISSN:0360-4012    

DOI:10.1002/jnr.490150109

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

年代:1986

数据来源: WILEY

摘要:

AbstractA study of the transport of3H‐hypotaurine by rat retina has been carried out. The process is markedly sodium and temperature dependent. Kinetic analysis of the data revealed two values for the affinity constant (K) of 4.91 μM and 1,071.3 μM. Some related and unrelated amino acids were examined as competitive inhibitors of3H‐hypotaurine transport. Only GABA and β‐alanine exhibited appreciable inhibitory activity. Taurine, glycine, and guanidine ethane sulfonate were not inhibitors.3H‐hypotaurine uptake was similarly distributed in the retinal subcellular fractions P1and P2. The active uptake of3H‐Hypotaurine by retinas of the rat and other species including chick and frog was studied and compared to cerebral cortex slices. The chick retina was similar to the rat in its capacity to transport hypotaurine whereas frog exhibited fourfold less activity. Slices of cerebral cortex from rat and chick exhibited hypotaurine uptake but again the magnitude of the transport was three to fourfold less than in the compara

ISSN:0360-4012    

DOI:10.1002/jnr.490150110

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

年代:1986

数据来源: WILEY

ISSN:0360-4012    

DOI:10.1002/jnr.490150111

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

年代:1986

数据来源: WILEY