Because renal water retention is a complication of
cirrhosis,
niravoline (RU 51,599), a novel kappa (
kappa) opioid receptor agonist which is known to cause a water diuresis under normal conditions, may be useful in the
therapy of chronic
liver diseases. Thus, the present study examined the effects of
niravoline on renal function in rats with
cirrhosis. Urine was collected during the 2 h period following the administration of vehicle (saline) in one groups of animals or
niravoline (3 mg/kg, i.v.) in another group. Urinary and plasma osmolality were measured prior to and 2 h after
niravoline in a third group of animals. Urine flow and natraemia were significantly higher after
niravoline (147 +/- 12 microL/min and 153 +/- 2 mmol/L, respectively) than after vehicle (27 +/- 7 microL/min and 146 +/- 1 mmol/L, respectively).
Niravoline significantly decreased urinary osmolality and significantly increased plasma osmolality and free water clearance. This substance did not significantly change urinary
sodium excretion. In conclusion, this study shows that
niravoline, a
kappa opioid receptor agonist, induced a water diuresis in rats with
cirrhosis.