Kainic acid stimulates GABA release from a subpopulation of cerebellar astrocytes

The effect of acute exposure to micromolar concentrations of kainic acid was studied in rat cerebellar astroglial cultures consisting of two antigenically and functionally distinct subpopulations of astrocytes. Kainate (20-100 microM) released [3H]GABA preaccumulated by A2B5-positive stellate astrocytes in a concentration-, Na+- and Ca2+-dependent way, and did not interfere with [3H]GABA transport. We hypothesize that kainate depolarizes this class of cells by activating cationic channels and that this results in an imbalance of GABAergic transmission.