The effect of noradrenaline, adrenergic blocking agents, and tyramine on the intrarenal distribution of blood flow in the baboon.

The intrarenal distribution of blood flow in the baboon was measured using the 133xenon clearance technique, and dose-response curves for the various components of renal blood flow were determined during intra-arterial infusions of noradrenaline; the alpha-adrenergic blocking agent, phenoxybenzamine; the beta-adrenergic blocking agent, propranolol; and tyramine which causes the release of endogenous NA. High doses of noradrenaline reduced flow in the outer cortex; this effect was attenuated by phenoxybenzamine, but not by propranolol. Tyramine had no effect. These r results suggest that there are alpha-adrenergic receptors in the resistance vessels of the kidney but are inconsistent with an important role for NA-mediated autonomic control of renal blood flow.