Wall thickness and constrictive responses of the caudal artery in rats with renovascular hypertension.

In rats with hypertension modeled by the one kidney-one clamp method, constrictory responses of the isolated caudal artery to norepinephrine differed under various perfusion conditions. Vascular reactions in hypertensive rats were more potent at a constant flow rate, and less potent at a constant pressure compared to those in normotensive rats. Previous experiments demonstrated similar changes in constrictory responses of the caudal artery in spontaneously hypertensive rats. It is assumed that these peculiarities of the vascular reactivity during hypertension are determined by thickening of the smooth muscle layer of the vascular wall.