A 5-HT1D receptor agonist selective for 5-HT1D over the 5-HT1A 5-HT1C 5-HT1E 5-HT2 and 5-HT3 receptors (Kis 0.093 2.29 380 2187 316 and >10000 nM respectively) inhibits forskolin-induced adenylyl cyclase activity in guinea pig substantia nigra homogenates and potassium-induced 5-HT release in isolated guinea pig frontal cortex strips (EC50s 0.79 and 0.4 nM respectively) decreases water intake in dehydrated rats as well as prevents carbachol- angiotensin II- or isoproterenol-induced increases in water intake in normohydrated rats intra-atrial administration (0.00000125-0.1 UG/kg) decreases renal perfusion pressure in in situ autoperfused rat kidney infused with phenylephrine