ANTIEPILEPTICS INHIBIT CORTICAL N-METHYL-D-ASPARTATE-EVOKED [H-3] NOREPINEPHRINE EFFLUX

The antiepileptic drugs phenytoin, valproic acid and phenobarbital wer e examined for their ability to inhibit N-methyl-D-aspartate (NMDA)-st imulated [H-3]norepinephrine efflux from rat brain cortical slices. Al l three drugs inhibited efflux at varying concentrations. Valproic aci d was the most potent and inhibited efflux at 0.01 mg/ml. Phenytoin an d phenobarbital inhibited efflux at 0.1 mg/ml. These results indicate that some antiepileptic drugs are capable of inhibiting NMDA receptor function in the therapeutic range.