Pharmacological properties of gamma-aminobutyric acid-, glutamate-, and aspartate-induced depolarizations in cultured astrocytes.

摘要: Differentiated glial fibrillary acidic protein-positive astrocytes in homogeneous cultures of early postnatal rat cerebral hemispheres respond by membrane depolarization to gamma-aminobutyric acid (GABA), glutamate, and aspartate with a threshold concentration approximately 10(-5) M. The GABA-induced is antagonized two blockers the neuronal GABAA receptor, picrotoxin bicuculline, but not affected uptake beta-alanine or nipecotic acid. An agonist muscimol, produces dose-response curve similar that GABA, whereas GABAB baclofen, did alter potential. When repetitive pulses GABA are given one cell, its responsiveness depends on time interval between pulses. Within 30 sec after termination first pulse cell remains unresponsive second pulse. With increased intervals pulses, reactivity toward recovers. Five minutes regains 75% initial peak. Aspartate results size course induced glutamate. glutamate agonists, quisqualate ibotenate, kainate less potent than N-Methyl-D-aspartate has no effect potential astrocytes. pharmacological features response therefore those receptor mediating transport.