Inhibition by vitamin D pretreatment of ATP-induced vasoconstriction in rats.

In the isolated perfused hind legs of rats, ATP-Na2 injections induce an increase of perfusion pressure. Maximum pressure increase, EAm, is comparable to maximum increase induced by norepinephrine or vasopressin. In vitamin D2-pretreated rats, ATP-Na2-induced pressure increase is strikingly decreased as it is the case when using norepinephrine or vasopressin as vasoconstrictors. Vasodepression seems to be due to unspecific impairment by vitamin D2 of contractile elements of the vessel wall.