The effect of angiotensin II on endogenous noradrenaline release in man.

1. Considerable data from animal studies suggest that angiotensin II exerts a facilitatory effect on noradrenaline release. We sought evidence for such an effect in man by examining how a subpressor dose of angiotensin II (1.5 ng kg-1 min-1) influences the haemodynamic and plasma noradrenaline responses to physiological stimulation of the sympathetic nervous system. 2. The physiological stimuli investigated were a cold pressor test, the response to standing from lying, bicycle exercise and forearm isometric exercise. 3. The presence of the angiotensin II infusion had no effect on the systolic blood pressure, diastolic blood pressure, heart rate or plasma noradrenaline responses to stimulation of the sympathetic nervous system. 4. We have therefore found no evidence to support the enhancement of noradrenaline release by this low dose of angiotensin II in man.