[Inhibitory processes in the cerebral cortex and the anticonvulsive action of benzodiazepine derivatives].

A comparative study of the effect of some benzodiazepine deprivatives (chlonazepam, lorazepam, diazepam, and medazepam) on the recovery cycles of the interzonal response was carried out on unanesthetized curare-immobilized cats. These drugs proved to selectively inhibit the testing potential within the range of 20 to 100 msec. between the conditioning and the testing stimuli. This indicates that potentiation of GABA-ergic inhibition in the cerebral cortex. The threshold doses of the drugs inducing the depression of the test response and of ED50, preventing the development of convulsions, caused by GABA deficiency or by GABA-ergic receptor block, were compared; a correlation between the mentioned effects was demonstrated. The significance of GABA-positive effect of benzodiazepines in the mechanism of their anticonvulsive activity is suggested.