Angiotensin converting enzyme inhibitors, regional vascular hemodynamics, and the development and prevention of experimental genetic hypertension.

Abstract

During the development of hypertension in young spontaneously hypertensive rats (SHR) vascular resistance is increased, particularly in the renal circulation, and, to a lesser extent, in the splanchnic bed. Treatment with angiotensin converting enzyme inhibitors in young SHR reverses the renovascular abnormalities more effectively than simple vasodilators, suggesting that the resistance changes may depend on angiotensin II. Perindopril treatment during the development of hypertension causes a reduction in blood pressure as a result of a fall in total peripheral resistance, which persists long after treatment is stopped. These long-term effects can be prevented by replacing angiotensin during perindopril treatment. Not all organs share the long-term resistance changes following perindopril treatment, which are most marked in the renal, splanchnic, and cerebral circulations. The heterogeneous patterns of regional vascular resistance during the development and after prevention of hypertension with angiotensin converting enzyme inhibitors in SHR suggest that local factors, for example, angiotensin II related to the tissue renin-angiotensin system or local adrenergic activity, may be important in the genesis of high blood pressure in this genetic model.