STIMULATORY EFFECT OF <scp>l</scp>‐GLUTAMATE AND RELATED AMINO ACIDS ON [³H]DOPAMINE RELEASE FROM RAT STRIATUM: AN <i>IN VITRO</i> MODEL FOR GLUTAMATE ACTIONS

Abstract

Abstract— The effects of l ‐glutamate and a number of structural analogues on the spontaneous release of [ 3 H]dopamine from slices of rat striatum were examined. Glutamate, and other excitatory amino acids produced a marked stimulation of [ 3 H]DA release which was Ca 2+ ‐dependent and unaffected by either procaine or tetrodotoxin. The glutamate‐stimulated release was abolished in kainate‐lesioned striatum. The action of glutamate was effectively antagonised by glutamamate diethylester and 2‐amino‐4‐phosphonobutyric acid, but only weakly by l ‐methionine‐ dl ‐sulfoximine. Other proposed amino acid antagonists were inactive. The likely site of the releasing action of l ‐glutamate on presynaptic sites on nigro‐striatal DA terminals is discussed.