GABAA/benzodiazepine receptors in acutely isolated hippocampal astrocytes

摘要: The properties of GABA receptor-mediated responses were examined in noncultured astrocytes, acutely isolated from the mature rat hippocampus. Whole-cell patch clamping revealed a GABA-activated Cl- conductance that was mimicked by GABAA receptor agonist muscimol and depressed antagonists bicuculline picrotoxin. GABAA-activated currents potentiated barbiturate pentobarbital benzodiazepine diazepam. inverse DMCM either enhanced or astrocytic GABAA-mediated responses, suggesting heterogeneity with respect to pharmacologic profiles. In addition, evoked an increase [Ca2+]n measured indo-1 fluorometry, which presence verapamil A GABAA-induced depolarization, therefore, causes Ca2+ influx through voltage-gated channels. expression subcellular localization receptors its subunits using immunohistochemical fluorescent binding techniques. Polyclonal antisera raised against GABAA/benzodiazepine receptor, recognizes multiple subunit isoforms, labeled on cell body most large processes. contrast, generated alpha 1 beta peptides immunoreactivity predominantly subset To determine distribution membrane-bound receptors, derivative superfused over live astrocytes visualized laser-scanning confocal microscopy. Specific fluorescence distributed discrete clusters soma distal Collectively, these data support view like neurons, express target isoforms distinct cellular localizations. Astrocytic may be involved both [Cl-]o [pH]o homeostasis, GABA-evoked [Ca2+]i could serve as signal between GABAergic neurons astrocytes.