Participation of GABAergic and histaminergic systems in inhibiting amygdaloid kindled seizures

The effects of GABAmimetic drugs on inhibition of amygdaloid kindled seizur es induced by clobenpropit were investigated to clarify the relationship be tween histaminergic and GABAergic systems in seizures. I.p. injection of cl obenpropit caused dose-dependent inhibition of amygdaloid kindled seizures. GABAmimetic drugs such as diazepam, sodium valproate and muscimol also inh ibited amygdaloid kindled seizures in a dose-dependent manner. Diazepam at doses of 0.2 and 0.5 mg/kg, which showed no significant effect on amygdaloi d kindled seizures when used separately, significantly potentiated the effe ct of clobenpropit. Similar findings were observed with sodium valproate an d muscimol at doses of 100 mg/kg and 5 ng, respectively, although neither s howed any significant effects when administered separately. Bicuculline cau sed significant antagonism of the inhibition of amygdaloid kindled seizures induced by clobenpropit, while the effect of diazepam was not antagonized by diphenhydramine. These results suggested that inhibition of amygdaloid k indled seizures induced by histamine is closely associated with the actions of GABA.