Angiotensin II potentiates the vasoconstrictive effect of norepinephrine in normotensive and hypertensive man

The renin-angiotensin system may effect blood pressure regulation by enhancing sympathetic activity. Angiotensin II given in subpressor doses has been shown to enhance the vasoconstrictive effect of norepinephrine in several animal models. However, the effects of subpressor doses of angiotensin II on the vasoconstrictor effects of norepinephrine have not been reported in humans. We found that angiotensin II, given in subpressor doses, potentiates the vascular response of norepinephrine in normotensive and hypertensive male subjects. These results demonstrate the important inter-relationship of the renin-angiotensin system to the sympathetic nervous system in normal and essential hypertensive man.