Benzodiazepines and central inhibitory mechanisms.

The effect of diazepam was evaluated on spontaneous activity and drug- and electrically-elicited inhibitions of neuronal activity. Doses of diazepam which did not change spontaneous firing rates markedly enhanced GABA-mediated inhibitions in rat cerebellum in situ and in tissue cultures of rat hypothalamus. The effects of diazepam were readily reversible, and could be antagonized by picrotoxin; no effect on glycine or norepinephrine-induced inhibition was seen. It is concluded that actions of diazepam are mediated, at least in part, by a specific increase in GABA-mediated inhibition in the central nervous system.