Effect of norepinephrine, isoproterenol, and adrenergic blockers upon the intrarenal distribution of blood flow

Abstract

The effect of intrarenal administration of norepinephrine, isoproterenol, and adrenergic blockers upon the intrarenal distribution of blood flow has been studied with the ⁸⁵Kr method. Norepinephrine produces marked vasoconstriction of the outer cortex while it increases the medullary blood flow rate. Isoproterenol had no effect of its own and antagonized the norepinephrine effect. Phenoxybenzamine produced no particular effect and prevented the hemodynamic modifications produced by norepinephrine. Phenoxybenzamine also unmasked the cortical vasodilating effect of isoproterenol. Propranolol was found to have an adrenergic-like effect on the cortical and medullary circulations which was inhibited by phenoxybenzamine. It is concluded that the cortical circulation is very reactive to vasoactive stimuli whereas the outer medulla seems to present a rather passive vascular bed.