新结构Rho激酶抑制剂对离体胸主动脉血管环舒张作用及机制研究

Vasorelaxant effect of novel Rho-kinase inhibitors on isolated thoracic aorta rings and underlying mechanisms

目的评价2个全新结构小分子Rho激酶抑制剂J35242和J35243对离体大鼠胸主动脉血管环的舒张作用,并探讨其作用机制。方法利用离体大鼠胸主动脉血管环模型,分别用高浓度KCl和去甲肾上腺素(norepinephrine,NE)预刺激,评价化合物的舒张血管活性;通过各种工具药干预,观察化合物舒张血管作用的内皮相关机制、钾通道相关机制和钙离子相关机制。结果 J35242和J35243可以剂量依赖性舒张高浓度KCl和NE预收缩的血管环,并呈现一定的内皮依赖性;L-NAME和亚甲蓝可在一定程度上影响其舒张作用;化合物还明显抑制由细胞内钙释放和外钙内流引起的血管收缩,说明其可能通过阻断钙离子通道发挥舒张血管作用;另外两个化合物可能不是通过开放钾离子通道发挥舒张血管作用。结论 J35242和J35243在体外具有一定的舒张血管作用,并且J35242的作用要强于J35243,其机制可能依赖于血管内皮功能,另外可能与抑制平滑肌细胞钙离子通道,降低细胞内钙离子浓度相关。

Aim To evaluate the vasorelaxant effect of two new chemical entities, J35242 and J35243, on iso-lated rat thoracic aorta rings as Rho-kinase inhibitors, and further to explore the underlying mechanisms of these two compounds. Methods Isolated rat thoracic aorta rings pre-contracted by KCl or norepinephrine （ NE） were used to evaluate the vasodilatory effect of J35242 and J35243 . Through the interventions of sev-eral tool drugs, the mechanisms of compounds concern-ing endothelium, K^＋ channels and Ca^2＋ were studied. Results J35242 and J35243 showed potent relaxant effect on both KCl and NE pre-contracted vessels, and exhibited partial endothelium dependency. L-NAME and Methylene Blue（ MB） could influence the relaxant effect of these compounds. Meanwhile, the compounds could inhibit intracellular Ca^2＋ release and extracellu-lar Ca^2＋ influx, which indicated that the compounds might block the calcium channels to relax the vessels. In addition, the two compounds probably did not dilate the aorta rings through opening potassium channels. Conclusions J35242 and J35243 have vasorelaxant effects on vessels in vitro and the potency of J35242 is stronger than that of J35243 . The underlying mecha-nisms might be endothelium-dependent. Also the com-pounds might block Ca^2＋ channels, lowering intracel-lular Ca^2＋ concentration to relax the vessels.