Effects of anticonvulsants on K+-induced excitation and on penicillin-induced seizures.

Excitation induced in mice by intracerebral injection of KCl was antagonized by prior i.p. injection of phenytoin, chlordiazepoxide or phenobarbital, but was not significantly affected by muscimol, valproate, ethosuximide or trimethadione. In contrast, seizures induced by intracerebral injection of benzyl penicillin were antagonised by chlordiazepoxide, phenobarbital, valproate, ethosuximide and trimethadione, but not by phenytoin or muscimol. Implications with regard to mechanisms of action of the anticonvulsants and of penicillin are discussed.