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Effects of urotensin Ⅱ on isolated rat hearts under normal perfusion and ischemia-reperfusion

Zhou Ping, Wu Shengying, Yu Chengfan, Wang Hua, Tang Chaoshu, Lin Li, Yuan Wenjun

Caridovascular Institute,First Hospital,Peking University.Beijing 100034；China

Abstract

(1)In normal rat hearts, the coronary flow was decreased and the heart function was suppressed by U II dose-dependently, and these changes were not abolished by washout. The leakage of cardiac protein, myoglobin and LDH increased with the increment of U II, but it diminished rapidly after washout. In contrast, MDA content in U II-treated myocardium was not statistically different from that in normal myocardium. (2) Ischemia-reperfusion caused significant decreases in coronary flow, suppression of heart function, and leakage of protein and LDH. In U II-reperfused hearts, all these disorders were significantly aggravated and myocardial MDA content significantly increased (P<0.01), to a greater extent in the presence of higher dose of U II. (3) The maximal binding capacity (B_(max)) of U II receptors in plasma membrane from ischemia-reperfusion myocardium increased significantly as compared with that of normal myocardium (20.53±1.98 vs 14.65±1.78 fmol/mg pr, P<0.01), while Kd remained unchanged. These results indicate that U II caused injury to the isolated rat hearts under normal perfusion, and worsened the injury of the hearts under ischemia-reperfusion, in which U II receptors were up-regulated.

Key words: Pathology;Urotensin Ⅱ;Isolated heart perfusion;Isehemia-reperfusion;Rat

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Citing This Article：

Zhou Ping, Wu Shengying, Yu Chengfan, Wang Hua, Tang Chaoshu, Lin Li, Yuan Wenjun. Effects of urotensin Ⅱ on isolated rat hearts under normal perfusion and ischemia-reperfusion. Acta Physiol Sin 2003; 55 (4): (in Chinese with English abstract).