Effects of human urotension II on in vivo mesenteric microcirculation in rats

AIM: To investigate the effects of human urotensin Ⅱ (hUII) on in vivo mesenteric microcirculation in rats. METHODS: For recording of microcirculation images in the mesentery, the intestinal loop was mounted on the stage of an intravital microscope equipped with a TV camera. Video images of microcirculation were stored by a video cassette recorder. Temporal changes in internal diameter and microcirculatory velocity of microvesseles were measured by computer using the ImagePro software. The blood flow in intestinal wall was measured with PIMII laser Doppler perfusion Imager (Lisca Sweden). RESULTS: The internal diameters of arterioles and venules in control group were (21.4±2.3) μm and (38.1±3.6) μm,respectively. In UII group, the arterioles and venules contracted immediately after treated with UII and up to the peak at 1 min [(14.1±1.4) μm and (22.2±5.2) μm vs control,P0.05]. Both microcirculatory velocity of arterioles and venules showed no significant changes in UII group (compared with control, P0.05). The blood flow in intestinal wall increased 1 min after treated with UII and up to high peak at 5 min(6.4±1.1 perfusion unit vs control 4.2±0.9,P0.05). CONCLUSION: hUII contracted mesenteric microvesseles in rats and increased microcirculatory blood perfusion in intestinal wall.