AJP - Endocrinology and Metabolism, Vol 262, Issue 1 E100-E104, Copyright © 1992 by American Physiological Society
Effects of an opiate receptor antagonist on renin release in dogs
M. D. Johnson and R. K. Cavender
Department of Physiology, West Virginia University Health Sciences Center, Morgantown 26506.
The present experiments were designed to determine whether blockade of
endogenous opiate receptors with naloxone would suppress renin release
induced by circulating epinephrine or by reductions of renal perfusion
pressure. In the first series of experiments, anesthetized dogs were
prepared with a flow probe around the left renal artery and a catheter in
the left renal vein, permitting measurement of renin secretion before,
during, and after 15-min infusions of epinephrine (50 ng.kg-1.min-1 iv).
The epinephrine infusions were conducted either before or after blockade of
opiate receptors with naloxone (1 mg/kg iv). Naloxone failed to alter the
renin secretory response to intravenous epinephrine infusion. In a second
series of experiments, anesthetized dogs were uninephrectomized and
prepared with a constrictor cuff around the left renal artery and a renal
arterial catheter distal to the cuff. After control measurements of renal
perfusion pressure and plasma renin activity (PRA), the cuff was
constricted at 15-min intervals to produce controlled stepwise reductions
of renal perfusion pressure ranging from 15 to 90 mmHg. One-half of the
animals was pretreated with naloxone (1 mg/kg iv). Naloxone pretreatment
had no effect on the PRA response to reduced renal perfusion pressure at
any pressure. The data fail to support the hypothesis that endogenous
opioid peptides are modulators in the control of renin release.
