Endothelin a receptor antagonist reduces renal vasoconstriction induced by mechanical manipulation of renal artery

The purpose of this study was to make a model of renal vasoconstriction induced by mechanical manipulation of the renal artery and to investigate the influence of endothelin (ET) in renal vasoconstriction. Renal arteries of anesthetized rats were stretched with a 30-gram weight for 5 min, and released. Renal blood flow (RBF) was monitored with a laser flowmeter. To determine the role of ET, a selective ETA receptor antagonist, BQ-123 (0.1 and 1 mg/kg) was administered into the aorta. The manipulation was invariably followed by a flow reduction of about 57% after temporary hyperemia. RBF returned to the basal level 5 min after the release. BQ-123 partially, but significantly, inhibited the mechanical manipulation-induced reduction of RBF in a dose-dependent manner. These results suggest that endogeneous ET may play an important role in renal vasoconstriction induced by mechanical manipulation of the renal artery. Copyright (C) 2000 S. Karger AG, Basel.