Functional evaluation of glutamate receptor subtypes in cultured cerebellar neurones and astrocytes.

Micromolar concentrations of kainic acid and quisqualic acid released [3H]D-aspartate preaccumulated by cerebellar granule cells in culture. The effect of kainate was selectively antagonized by kynurenic acid and, less effectively, by PDA. Kainate and quisqualate also increased [3H]GABA release from a subpopulation of cultured cerebellar astrocytes. Kynurenic acid selectively blocked the effect of kainic acid. NMDA and no D-aspartate or GABA releasing effect. These results suggest the existence of two different excitatory amino acid sites active on neurotransmitter amino acid release in both cerebellar granule cells and astrocytes.