An agonist of 5-HT1B and 5-HT1D receptors (IC50s = 12 and 13 nM, respectively, in a radioligand binding assay); selective for human 5-HT1B and 5-HT1D receptors over rat 5-HT1A and human 5-HT2A and 5-HT4 receptors (IC50s = 0.85, 25.1, and 140 μM, respectively); induces contractions in isolated canine saphenous veins (EC50 = 394 nM) but not isolated rabbit renal or mesenteric arteries; increases carotid vascular resistance in anesthetized cats (ED100 = 11 μg/kg, i.v.) without increasing blood pressure or heart rate