内皮素-1对离体豚鼠工作心脏的作用

在离体豚鼠工作心脏模型上,单次推注内皮素-1(ET-1·30,90,300pmol·L~(-1))能引起初始短暂的正性肌力作用及随后持续的负性肌力,负性频率作用。低剂量的ET-1(30,90,pmol·L~(-1))能使心脏各功能指标可逆性恢复.而高剂量的ET-1(300pmol·~(-1))则强烈收缩冠脉,造成心肌缺血,LDH值升高,最终导致心功能指标显著受抑。环氧化酶抑制剂In-domethacin 30 μmol·L~(-1)能显著增强ET-l收缩冠脉血管的作用,加重心肌缺血。上术结果表明:ET-1通过强烈收缩冠脉血管,造成心肌缺血而引起离体豚鼠工作心脏心功能的抑制。并提示PGI_2能显著拮抗ET-1的缩血管作用。

Effects of ET on the function of the isolated perfused working guinea pig heart

The effect of endothelin (ET-1) on the function of the isolated perfused working guinea pig has been examined. ET- 1 wasshowed to exert a transient positive inotropic effect on the isolated heart, followed by a marked inhibition of cardiac function. Low dose of ET- 1(30,90 pmol·L-1) produced reversible inhibition. The effect of high dose of ET- 1 was irreversible, accompanied with increasing LDH significantly, indomethacin markedly augmented the vasoconstrictor and cardiac ischemia effects of ET-1. Our results suggest that the apparent inhibition of cardiac function on the isolatedperfused guinea pig heart after administration of ET-1 may be due to the effect of the myocardial ischaemia caused by progressive development of coronary vasoconstriction. In our experimental model, PGI2 has partially antagonizing effect on the vasoconstrictor action of ET-1.