DA1受体激动剂对大鼠离体肺动脉内皮依赖性舒张反应的影响

目的 :探讨多巴胺 1(DA1)受体激动剂非诺多泮 (FODA)对大鼠离体肺动脉内皮依赖性舒张反应的反应机制。方法 :利用离体血管微量生物反应检测技术 ,分别观察FODA对离体肺动脉内皮依赖性舒张反应以及N L 精氨酸甲硝基酯 (L NAME)、甲烯兰 (MB)、优降糖、左旋精氨酸 (L arg)对FODA引起肺动脉内皮依赖性舒张反应的影响。结果 :①L NAME明显降低完整内皮的肺动脉环对FODA的舒张反应 ;②L NAME对FODA引起肺动脉内皮依赖性舒张反应的抑制反应能够被L arg翻转 ;③MB亦可明显减弱FODA对肺动脉的舒张反应 ;④ATP钾离子通道阻滞剂优降糖则不影响FODA引起肺动脉内皮依赖性舒张反应。结论 :DA1受体激动剂对肺血管的内皮依赖性舒张反应主要是通过内皮舒张因子 (EDRF)NO引起的 ,而内皮超极化因子 (EDHF)不参与这一过程。

Mechanism of endothelium-dependent vasorelaxing response to dopamine-1 receptor agonist in rat pulmonary artery

Aim:To study the mechanism of the endothelium-dependent vasorelaxing response to agonist of DA1 receptor in rat isolated pulmonary artery.Methods:Endothelium-dependent relaxation of pulmonary artery to dopamine receptor agonist,fenoldopam, was examined with vascular ring.Results:①L-arg methyl ester(L-NAME),a specific inhibitor of nitric oxide(NO) formation,reduced remarkably the vasorelaxing response of pulmonary arterial rings with intact endothelium to fenoldopam;②The inhibitory action of L-NAME could be reversed by addition of L-arginine;③Methylene blue (MB),an inhibitor of guanylate cyclase,also significantly reduced the pulmonary vasorelaxing response to fenoldopam;④No effects was observed for glibenclamide,a blocker of ATP-sensitive potassium channels,on fenoldopam-induced endothelium dependent vasorelaxation in the pulmonary artery.Conclusion:The function of the DA1 receptor agonist-inducing vasorelaxation is mainly mediated by NO which accounts for the biological activity of endothelium-derived relaxing factor(EDRF),while endothelium-derived hyperpolarizing factor(EDRF)may not be involved in this process.