A partial agonist of GABAB receptors (IC50 = 1.5 μM in a radioligand binding assay); induces relaxation in unstimulated isolated guinea pig ileum longitudinal muscle; completely inhibits GABA- and baclofen-induced inhibition of vagally stimulated bronchospasms in guinea pigs (5 mg/kg); reverses the antitussive effect of baclofen in cats (3 mg/kg)