AJP - Heart and Circulatory Physiology, Vol 244, Issue 1 39-H45, Copyright © 1983 by American Physiological Society
Effect of intrarenal administration of dopamine on renin release in conscious dogs
H. Mizoguchi, V. J. Dzau, L. G. Siwek and A. C. Barger
We investigated the effect of intrarenal administration of dopamine on
renin release in conscious dogs. Dopamine in doses ranging from 0.28 to 3.0
micrograms . kg(-1) . min(-1) produced a significant increase in systemic
plasma renin activity (PRA) and renin secretion rate without altering
systemic blood pressure. Dopamine also induced renal vasodilatation and
natriuresis within this dose range. To determine if the dopamine-induced
renin release is related to its vasodilatory action, two other
vasodilators, papaverine and acetylcholine, were infused into the renal
artery, but neither, in doses that produced a rise in renal blood flow
similar to that of dopamine, 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. In contrast,
intrarenal infusion of propranolol failed to alter dopamine-induced rise in
PRA or renal blood flow. Simultaneous infusion of phentolamine and
dopamine, on the other hand, produced a significant potentiation of
dopamine-induced renin release and renal vasodilatation. In conclusion, our
studies demonstrate that dopamine is capable of inducing renin release and
renal vasodilatation in conscious dogs. Moreover, such actions of dopamine
are mediated through activation of specific dopamine receptors in the
kidney. Finally, we present evidence for the existence of the intrarenal
alpha-adrenergic mechanism that is inhibitory to renin release.
