[Effects of an endogenous GABA receptor binding inhibitor on rat blood pressure].

The GABA receptor agonists GABA (400 micrograms icv) and muscimol (1 microgram icv) induced hypotension in urethane-anesthetized rats, while the GABA receptor antagonist bicuculline (2 micrograms icv) elicited hypertension. An endogenous GABA receptor binding inhibitor (1 mg), prepared from bovine cerebellum, showed bicuculline-like hypertensive action in a dose-dependent manner. It was antagonized by icv muscimol, but not by the alpha 2-adrenoceptor agonist clonidine. These in vivo results agree quite well with our previous in vitro receptor binding assay experiments.