Ethanol inhibits epileptiform activity and NMDA receptor-mediated synaptic transmission in rat amygdaloid slices.
The effect of ethanol on the epileptiform activity induced by Mg(++)-free solution was studied in rat amygdalar slices using intracellular recording techniques. The spontaneous and evoked epileptiform discharges consisting of an initial burst followed by afterdischarges were observed 20-30 min after switching to Mg(++)-free medium. Superfusion with ethanol (20-100 mM) reversibly reduced the duration of spontaneous and evoked bursting discharges in a concentration-dependent manner. Synaptic response mediated by N-methyl-D-aspartate (NMDA) receptor activation was isolated by application of a solution containing the non-NMDA receptor antagonist 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX) and either in Mg(++)-free solution or in the presence of 50 microM bicuculline. Application of ethanol reversibly suppressed the duration of NMDA receptor-mediated synaptic response. These results suggest that intoxicating concentrations of ethanol possess anticonvulsant activity through blocking the NMDA receptor-mediated synaptic excitation. In addition, the observed effect of ethanol on NMDA receptor-mediated synaptic response could be relevant to the cognitive and behavioral manifestations seen in some alcoholics.
Department of Pharmacology, College of Medicine, National Cheng-Kung University, Tainan City, Taiwan, R.O.C.
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D018750:6-Cyano-7-nitroquinoxaline-2,3-dione; D000679:Amygdala / Q000187:drug effects / Q000502:physiology*; D000818:Animals; D000927:Anticonvulsants / Q000494:pharmacology*; D001640:Bicuculline / Q000494:pharmacology; D003864:Depression, Chemical; D004827:Epilepsy / Q000503:physiopathology*; D000431:Ethanol / Q000494:pharmacology*; D066298:In Vitro Techniques; D008274:Magnesium / Q000502:physiology; D008297:Male; D008564:Membrane Potentials / Q000187:drug effects; D011810:Quinoxalines / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains; D016194:Receptors, N-Methyl-D-Aspartate / Q000187:drug effects / Q000502:physiology*; D013569:Synapses / Q000187:drug effects / Q000502:physiology*; D009435:Synaptic Transmission / Q000187:drug effects*
D000927:Anticonvulsants; D011810:Quinoxalines; D016194:Receptors, N-Methyl-D-Aspartate; D000431:Ethanol; D018750:6-Cyano-7-nitroquinoxaline-2,3-dione; D008274:Magnesium; D001640:Bicuculline