Effect of intrarenal administration of dopamine on renin release in conscious dogs

Abstract

The effect of intrarenal administration of dopamine on renin release in conscious dogs was investigated. Dopamine in doses ranging from 0.28-3.0 .mu.g .cntdot. kg-1 .cntdot. min-1 produced a significant increase in systemic plasma renin actiivity (PRA) and renin secretion rate without altering systemic blood pressure. Dopamine also induced renal vasodilation and natriuresis within this dose range. To determine if the dopamine-induced renin release is related to its vasodilatory action, 2 other vasodilators, papaverine aned acetylcholine, were infused into the renal artery; in doses that produced a rise in renal blood flow similar to that of dopamine, neither had any effect on PRA. As dopamine can activate .alpha.- and .beta.-adrenergic receptors in addition to dopaminergic receptors, experiments were also performed to characterize the type of receptors involved in dopamine-induced renin release. Intrarenal infusion of sulpiride and haloperidol, dopamine antagonists, significantly inhibited dopamine-induced renin release and renal vasodilatation. Intrarenal infusion of propranolol failed to alter dopamine-induced rise in PRA or renal blood flow. Simultaneous infusion of phentolamine and dopmaine produced a significant potentiation of dopmaine-induced renin release and renal vasodilatation. Apparently, dopamine is capable of inducing renin release and renal vasodilation in conscious dogs. Such actions of dopamine are mediated through activation of specific dopamine receptors in the kidney. Evidence is presented for the existence of the intrarenal .alpha.-adrenergic mechanism that is inhibitory to renin release.