POTENTIATION OF N-METHYL-D-ASPARTATE RECEPTOR-DEPENDENT AFTERDISCHARGES IN RAT DENTATE GYRUS FOLLOWING IN-VITRO ETHANOL WITHDRAWAL

The contribution of NMDA receptors to neuronal hyperexcitability follo wing in vitro ethanol withdrawal was examined using afterdischarges (A Ds) in rat dentate gyrus as a model system. ADs were evoked by high fr equency stimuli and blocked by N-methyl-D-aspartate (NMDA) receptor an tagonists. Ethanol (75 mM) inhibited ADs, and following in vitro ethan ol withdrawal, the duration of afterdischarges was significantly enhan ced (37 +/- 2%, n = 21). Therefore, in vitro ethanol exposure with sub sequent withdrawal is associated with an enhancement of NMDA receptor- dependent afterdischarges. These results are consistent with the invol vement of NMDA receptors in ethanol withdrawal hyperexcitability.