Effect of endothelin-1 (1-31) on the renal resistance vessels

Human chymase produces not only angiotensin II but also endothelin(ET)-1(1-31). We previously reported that ET-1(1-31) had several biological activities in vascular smooth muscle cells. In this study, we investigated the vasoconstrictor effect of ET-1(1-31) on the renal resistance vessels using in vitro micro perfused rabbit afferent and efferent arterioles.ET-1(1-31) decreased the lumen diameter of the afferent and efferent arterioles dose-dependently.ET-1(1-31)-induced afferent arteriolar vasoconstriction was not affected by phosphoramidon, an ET converting enzyme inhibitor. ET-1(1-31)-induced renal arteriolar vasoconstriction was inhibited by BQ123, an ETA receptor inhibitor, but not by BQ788, an ETB receptor inhibitor. These results suggest that ET-1(1-31)-induced renal arteriolar vasoconstriction may be mediated by ETA-like receptors.