摘要:

AbstractThe kinetics and dynamics of glial fibrillary acidic protein (GFAP) assembly was explored by a fluorescence energy transfer assay method. Purified GFAP was stoichiometrically labeled at a single cysteine residue with fluorescein‐maleimide. Soluble labeled GFAP in a low ionic strength buffer was assembled into 10 nm filaments by rapidly increasing the ionic strength, and the kinetics of GFAP assembly was monitored by the reduction in fluorescence due to self‐quenching of fluorescein. The extent of fluorescence quench correlated with both the formation of 10 nm filament morphology and the amount of protein pelleted at 12,000g. The assembly of GFAP is critically dependent upon both protein and magnesium ion concentration, and at the critical concentration for GFAP assembly is ∼ 40 μg/ml. Disassembly of GFAP filaments was also observed as a relief of fluorescence quenching after dilution of labeled GFAP filaments. When labeled GFAP filaments were mixed with an excess of unlabeled filaments, a rapid increase of fluorescence was observed, which is due to an exchange of subunits between labeled and unlabeled GFAP filaments. These results indicate that GFAP filaments are dynamic structures and that a small pool of kinetically active unassembled GFAP subunits are in a dynamic equilibrium with assembled GFAP filaments. The ability of GFAP to assemble, disassemble, and undergo subunit exchange has important implications for the organization and dynamics of astroglia cell cytoskeleton during development and in response to

ISSN:0894-1491    

DOI:10.1002/glia.440040112

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

年代:1991

数据来源: WILEY

摘要:

AbstractThe cytotoxic effect of quisqualate, a potent excitatory amino acid (EAA), was examined in purified astrocyte cultures obtained from neonatal rat cerebral cortex and grown in a serum‐free, defined medium (G5). Excitotoxicity was evaluated by phase contrast microscopy and quantified by the measurement of lactic dehydrogenase (LDH) activity released from the damaged cells into the culture medium. Quisqualate evoked not only osmotic swelling, but also cytotoxic cell death of cultured astrocytes. The vulnerability of cells was restricted to a period between day 4 and 8 in subculture, with a maximal sensitivity on day 7. The present findings indicate that not only neurons, but also glial cells may exhibit excitotoxic vulnerability. The vulnerability to quisqualate appears to be a transient phenomenon, at least in cultured astrocyte

ISSN:0894-1491    

DOI:10.1002/glia.440040113

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

年代:1991

数据来源: WILEY

摘要:

AbstractUltrastructural changes in rat astrocytes including endfoot swelling and rupture of plasma membranes were seen as early as 1 h after injection of 6.0 μg colchicine (CO) into the striatum. Significant change in neuronal morphology was not seen by 24 h. Astrocytes may therefore be primary targets for CO‐mediated damage, which then may have secondary neurotoxic consequenc

ISSN:0894-1491    

DOI:10.1002/glia.440040114

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

年代:1991

数据来源: WILEY

ISSN:0894-1491    

DOI:10.1002/glia.440040101

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

年代:1991

数据来源: WILEY