Abstract
Combined treatment of diphenylhydantoin (DPH) and diazepam exerted a stronger protective effect than either of the drugs alone, against electroshock induced seizures. The effect of combined treatment of DPH and diazepam was also observed against seizures induced by three chemical agents viz. pentylenete-trazol, bicuculline and isoniazid, whose action is attributed to the impairment of GABA-mediated inhibition. The potentiation by DPH of the anticonvulsant action of diazepam against pentylenetetrazol induced seizures and the simultaneous lack of such effect against seizures induced by bicuculline and isoniazid tends to exclude GABA-ergic mechanisms. It is suggested that DPH induced increase in the total number of specific benzodiazepine-binding sites could be responsible for the enhancement of the anticonvulsant action of diazepam against seizures induced by electroshock and pentylenetetrazol.