A dopamine D2 receptor agonist; selective for D2 over D1, D3, and D4 receptors (Kis = 9.0, >7,140, 1,940, and >2,190 nM, respectively); inhibits forskolin-stimulated cAMP accumulation in CHO cells expressing human recombinant D2A receptors (EC50 = 17 nM); decreases plasma prolactin levels in rats at ≥3.1 µmol/kg; inhibits dopamine neuron firing in the SNPC in anesthetized rats (ED50 = 2.3 µmol/kg); increases horizontal locomotor activity in a reserpinized, AMPT rat model of Parkinson's disease at ≥12.5 µmol/kg; decreases time spent in the open arms of the elevated plus maze and time spent immobile in the forced swim test in mice with SNPC lesions at 0.1 mg/kg; reduces premature responding by rats in the 5CRTT compared with untreated animals at ≥0.1 mg/kg