Angiotensin II attenuates the vasodilating effect of a nitric oxide donor, glyceryl trinitrate: roles of superoxide and angiotensin II type 1 receptors.

Objective: The development of tolerance to organic nitrates limits their usefulness in the treatment of heart disease. Activation of the renin-angiotensin system by heart failure itself and by nitrate therapy may be one possible mechanism underlying nitrate tolerance. We investigated the effect of subpressor doses of angiotensin II on the vasodilating effect of glyceryl trinitrate in human forearm resistance vessels of healthy male subjects by using venous occlusion strain-gauge plethysmography.