Differential effects of baclofen, gamma-hydroxybutyric acid and muscimol on the protective action of phenobarbital and diphenylhydantoin against maximal electroshock-induced seizures in mice.

This study was designed to compare the effects of baclofen (a GABAB agonist), muscimol (a GABAA agonist) and gamma-hydroxybutyric acid on the protective action of phenobarbital (PB) and diphenylhydantoin (DPH) against electroshock-induced convulsions. All drugs were given intraperitoneally, muscimol being also injected intraventricularly in a dose of 50 ng per mouse. It was found that both baclofen and gamma-hydroxybutyric acid potentiated the anticonvulsant activity of phenobarbital, being ineffective regarding the action of diphenylhydantoin. Conversely, muscimol injected by two different routes moderately enhanced the efficacy of diphenylhydantoin but remained without a significant effect upon the action of phenobarbital.