FURTHER EVIDENCE FOR GABA-ERGIC MECHANISMS IN ACTION OF BENZODIAZEPINES

Abstract

Drugs of the benzodiazepine series (clonazepam, lorazepam, diazepam and medazepam) increased the inhibitory processes in the cerebral cortex as shown by the recovery cycles of the intracortical response. There was a correlation between the effect on the recovery cycles and their protective action against convulsions induced by GABA deficit. Diazepam enhanced the inhibitory effect of GABA applied iontophoretically to rabbit sensorimotor cortex neurons. The durg GABA-ergic effect seemed to be specific since it failed to modify the effects of other purative neurotransmitters (glutamate, glycine, acetylcholine). The alteration of rat conflict situation behavior under diazepam was eliminated due to the blockade of GABA receptors by bicuculline and the decrease of the GABA level by thiosemicarbazide. The main effects of benzodiazepines may be mediated by GABA and these agents may increase the sensitivity of postsynaptic GABA-ergic receptors.