Urotensin II evokes potent vasoconstriction in humans in vivo

Abstract

The peptide urotensin II (U II) evokes potent vasoconstriction in non-human primates. In human blood vessels studied in vitro variable effects of U II are reported; vasoconstriction, vasodilatation or no response. It is therefore of importance to determine the vascular effect of U II in humans in vivo. U II (0.1 - 300 pmol min(-1)) was infused into the brachial artery of nine healthy volunteers. Changes in forearm blood flow (FBF) were determined by venous occlusion plethysmography. U II induced dose-dependent reduction in FBF. A threshold response was obtained by 1 pmol min(-1), and the highest dose of U II (300 pmol min(-1)) reduced FBF by 31+/-4% (P<0.01). FBF returned to baseline values within 30 min. This study demonstrates that U II produces potent vasoconstriction in humans in vivo.

Figure 1

Effect of urotensin II on forearm blood flow. Values are expressed (A) as per cent change in flow and (B) in absolute blood flow. Data are given as mean values and s.e.means (n=9). Significant differences from pre-infusion values (Time 0) are shown; ^*P<0.05, ^**P<0.01.