Vasopressin induces endothelium-dependent relaxations of cerebral and coronary, but not of systemic arteries.

Vasopressin causes relaxations of isolated basilar and left circumflex coronary arteries of the dog. After removal of the endothelium the inhibitory effect of vasopressin is abolished in the basilar and reduced in the coronary arteries. By contrast, vasopressin causes contractions of femoral arteries, which are not affected by the removal of endothelium. Indomethacin, nordihydroguaiaretic acid, atropine, propranolol and cimetidine do not reduce the inhibitory effect of vasopressin in basilar arteries. However, the V1-vasopressinergic antagonist d(CH2)5Tyr(Me)AVP blocks the vasopressin-induced relaxations, indicating that the effect of the hormone on the endothelium is mediated by activation of specific V1-vasopressinergic receptors.