Influence of ethanol on the threshold for electroshock-induced seizures and electrically-evoked hippocampal afterdischarges

Summary. The anticonvulsant activity of ethanol was investigated in two representative models of experimental epilepsy. In the maximal electroshock seizure threshold test in mice, ethanol (0.5–2 g/kg i.p.) dose-dependently raised the electroconvulsive threshold for tonic seizures. In co-medication with valproate and carbamazepine, ethanol significantly increased the anticonvulsant effectiveness of both antiepileptic drugs. Subchronic premedication of ethanol did not reveal marked decrease of its additive anticonvulsant action and only tended to reduce the effectiveness of valproate and carbamazepine. No changes of the plasma levels of both antiepileptics could be detected. Furthermore, in the hippocampal afterdischarge model in rats, ethanol dose-dependently raised the focal stimulation threshold and significantly increased the anticonvulsant efficacy of co-administered carbamazepine after acute application. Subchronic premedication of ethanol tended to reduce the effectiveness of the latter. In conclusion, the present results indicated pronounced anticonvulsant effects of ethanol against generalized tonic-clonic as well as complex partial seizures which did not reveal strong tolerance after subchronic administration.