Ameliorating effect of an endothelin ETA receptor antagonist on renal function of DOCA-salt hypertensive rats

The effects of FR139317 ((R)2-[(R)-2-[(S)-2-[[1-(hexahydro-1 H-azepinyl)]-carbonyl]amino-4-methyl-pentanoyl]amino-3[3-(1-methyl -1 H-indolyl)]propionyl]amino-3-2(2-pyridyl)propionic acid), an endothelin ETA receptor antagonist, on renal hemodynamics and urine formation were examined using anesthetized deoxycorticosterone acetate (DOCA)-salt hypertensive rats, in which renal perfusion pressure was protected from FR139317-induced hypotension with an aortic clamp. An intravenous injection of FR139317 (10 mg/kg) to sham-operated normotensive control rats produced no significant changes in renal hemodynamic and excretory responses. In DOCA-salt hypertensive rats, FR139317 caused sustained renal vasodilation. Urine flow and urinary excretion of sodium were increased significantly following drug injection. We suggest that endothelin-1 and the endothelin ETA receptor play an important role in water and sodium retention, and in renal vasoconstriction in this model of hypertension.