Central effects of endogenous and exogenous GABA.

Exogenous GABA administered into the lateral ventricle of the brain in Wistar rats in doses of 75, 200 and 600 microgram per rat, and endogenous GABA whose cerebral level was raised by intraperitoneal administration of hydroxylamine (Hx) in doses of 30, 50 and 75 mg/kg had a significant inhibitory effect on the central nervous system. This effect was abolished by bicuculine (Bc). The central effect of exogenous and endogenous GABA was manifested by reduced spontaneous and exploratory locomotor activity, decreased body temperature, potentiation of hexobarbital and chloral hydrate general anaesthesia and increase of haloperidol-induced catalepsy. On the other hand, no effect of GABA was observed on motor hyperactivity induced with amphetamine and on stereotypy induced with amphetamine and apomorphine.