[Synergism of picrotoxin with the endogenous convulsants kynurenine and quinolinic acid and its antagonism with their antagonists].

In experiments on mice the existence of common mechanisms of action was revealed in picrotoxin and kynurenine and quinolinic acid. Picrotoxin selectively potentiated convulsions induced by kynurenine and quinolinic acid and the antagonists of these endogenous convulsants--picolinic, kynurenic and xanthurenic acids--selectively antagonized picrotoxin convulsions. GABA-ergic preparations, effective in kynurenine convulsions and the anticonvulsants diazepam and phenobarbital, were highly effective against picrotoxin-induced convulsions also. Puphemid and trimethin indicated for treating petit mal epilepsy, proved ineffective. The obtained data suggest the possibility of action of kynurenine and quinolinic acid via picrotoxin-sensitive subunits of the benzodiazepine-GABA-receptor-ionophore complex.