This report describes an intracerebroventricular technique of drug injection which enables compounds with GABAergic properties to be rapidly identified in vivo. In addition, this method allows for the testing of compounds that poorly penetrate the blood brain barrier for GABAergic activities. Subcutaneous administration of apomorphine (1.5 mg/kg, SC) elicits climbing behavior in mice. The apomorphine-induced climbing behavior is inhibited by the intracerebroventricular or intraperitoneal administration of known GABA (gamma aminobutyric acid) agonists including muscimol (10-50 ng) and GABA (2-10 micrograms). This inhibitory effect of GABA or muscimol on apomorphine-induced climbing behavior can be reversed by picrotoxin (2 mg/kg, IP), a known GABA-receptor antagonist.