蛇床子素对大鼠离体胸主动脉的舒张作用

Vasorelaxation of Rat Thoracic Aorta Caused by Osthole

目的:研究蛇床子素对大鼠胸主动脉的舒张作用并探讨其机制。方法:采用大鼠胸主动脉环张力测定法,观察蛇床子素对苯肾上腺素(PE)和氯化钾(KCl)预收缩的大鼠离体胸主动脉的舒张作用。结果:蛇床子素在不改变血管基础张力的情况下能明显抑制由PE或KCl诱导的大鼠胸主动脉环收缩,其血管舒张作用为非血管内皮依赖性。在无Ca2+溶液中,蛇床子素不能抑制咖啡因或PE诱导的细胞内钙的释放,但添加Ca2+后,蛇床子素能够抑制KCl诱导的细胞外钙内流。结论:蛇床子素的血管舒张作用是非血管内皮依赖性的,其机制可能是通过阻断血管平滑肌细胞上的钙离子通道,抑制细胞外Ca2+内流而起作用的。

Objective： To investigate the vasorelaxant effect of osthole in rat aortic rings and the mechanism. Methods： The isolated thoracic aortic rings of male Wistar rats were mounted on the organ bath and the contractile responses of the vessel were recorded. Results： Osthole completely relaxed the contractions induced by phenylephrine or KCl in a concentration- dependent manner in endothelium-intact and endothelium-denuded rat aorta,but it had no effect on basic tension of aortic rings. In Ca2＋-free Krebs solution containing high K＋,the cumulative addition of Ca2＋caused at stepwise increase in contraction. Osthole inhibited this contraction in a concentration-dependent manner. But,osthole did not affect phasic contraction induced by caffeine or PE. Conclusion： Osthole induces an endothelium-independent relaxation in rat aortic rings. All these data indicate that osthole is a Ca2＋channel blocker,and that inhibitory effects of osthole on contractile responses in the rat thoracic aorta is due to an inhibition of Ca2＋influx.