BOSENTAN IMPROVES RENAL REGIONAL BLOOD-FLOW IN RATS WITH EXPERIMENTALCONGESTIVE-HEART-FAILURE

The effects of the mixed endothelin receptor antagonist bosentan on re nal regional haemodynamics were investigated in rats with aorto-caval fistula, an experimental model of congestive heart failure. A matched group of normal rats served as control. Injection of bosentan (10 mg/k g i.v.) to the rats with decompensated congestive heart failure produc ed an increase in cortical (+ 20%) and medullary (+ 12%) blood flow, a nd a decrease in vascular resistance in the cortex (- 30%) and medulla (- 23%), while reducing mean arterial pressure by approximately 10 mm Hg. In rats with compensated congestive heart failure and in normal a nimals, infusion of bosentan did not affect blood pressure and cortica l perfusion. These findings indicate that 1) endothelin receptor block ade produces beneficial effects on renal haemodynamics in rats with ex perimental congestive heart failure and 2) endothelin-1 may be involve d in the pathogenesis of renal hypoperfusion only in decompensated con gestive heart failure.