Amygdaloid kindling and kindled seizures in rats receiving chronic ethanol administration.

The effects of chronic ethanol administration were studied in rats receiving amygdaloid kindling. Daily ethanol administration 10 min prior to kindling stimulation delayed acquisition of kindling without affecting the electrical afterdischarge. For the lowest tested dose of ethanol (0.5 g/kg), this delay was restricted to kindling stages 1 and 2. For the higher doses of ethanol (1.0 and 1.5 g/kg) this delay became more severe and stages 3 and 4 were blocked. Ethanol produced a clear dose-related anticonvulsant effect upon kindled seizures. After repeated exposure to kindling stimulation and ethanol this anticonvulsant effect vanished. After a 15-day interval without stimulation or ethanol application kindled animals were insensitive to ethanol's anticonvulsant effect. In conclusion, it is suggested that the anticonvulsant effects of low ethanol doses are restricted to kindling stages 1 and 2 and that anticonvulsant effects of high ethanol doses are limited by tolerance and by the level of consolidation of the kindled seizure. Finally, we suggest that the anticonvulsant properties of ethanol are not due to its general depressant effect but to some rather specific action.