Differences in Anionic Dependence of the Synaptic Efflux of d‐Aspartic Acid and γ‐Aminobutyric Acid

Abstract
The synaptosomal effluxes of D-aspartate and .gamma.-aminobutyric acid (GABA) induced by a substitution of the Cl- ions with propionate in the incubation medium were measured in preparations of hippocampal tissue homogenates. The efflux of aspartate was significantly higher than spontaneous efflux at 125 mM Cl- (normal = 144 mM) and was increased with decreasing Cl- concentration. GABA efflux was much less sensitive to a reduction in Cl- concentration than D-aspartate. The efflux was Ca2+-dependent in both cases.