Comparative convulsant activity of various penicillins after intracerebral injection in mice

Abstract

The convulsant effects of penicillin derivatives (penicillin G, Phenoxymethylpenicillin, penicillin O, ampicillin, methicillin) and cephaloridine have been evaluated after being given intracerebrally to mice. Penicillin G was most neurotoxic; ampicillin and Phenoxymethylpenicillin were one-fifth as toxic. Incubation with penicillinase markedly reduced or eliminated the convulsant effects of penicillin G, Phenoxymethylpenicillin and ampicillin; this enzyme incubation did not alter the severity of seizures elicited by methicillin and cephaloridine. Diphenylhydantoin and phenobarbitone did not reduce penicillin G-induced seizures. A non-convulsant dose of leptazol potentiated the convulsions produced by the penicillins and cephaloridine. Injection volume, pH and the concentration of sodium and potassium did not produce behavioural changes within the ranges studied.