Release of endogenous ATP from the caudal artery in rats with arteriosclerosis.

Noradrenaline significantly increased (by a prazosin-sensitive mechanism) the overflow of ATP and its metabolites from the caudal arteries of rats treated with excess vitamin D2 and a high-cholesterol diet (arteriosclerotic rats), although the amount of the overflow was smaller than that in the normal rats. The arteries from the arteriosclerotic rats showed a marked increase in the calcium content and there was a significant negative correlation between the noradrenaline-induced overflow of ATP and the arterial calcium content. These findings indicate that ATP release from arteriosclerotic rat caudal arteries mediated by alpha 1-adrenoceptors is impaired in proportion to the extent of arterial calcification.