模拟失重对肺动脉反应性的影响

Effects of simulated weightlessness on reactivity of pulmonary artery

目的：研究模拟失重对肺动脉反应性的影响，探讨立位耐力降低的发生机制。方法：采用尾悬吊模拟失重大鼠模型模拟微重力效应，制备离体肺动脉环测定其对几种血管活性物质的反应性变化。结果：与对照组相比，尾悬吊14d大鼠肺动脉对KCl（68mmol／L）和苯肾上腺素（10^-9-10^-5mmol／L）的收缩反应性明显下降，对乙酰胆碱（10^-9-10^-5mmol／L）的舒张反应性明显增强。结论：模拟失重14d后肺动脉收缩反应下降，舒张反应增强；肺动脉收缩反应的下降可能促进了立位耐力降低的发生。

Objective：To study the effects of simulated weightlessness on reactivity of pulmonary artery. Methods：Rat tail-suspension was used to simulate effects of microgravity. The changes in responses of pulmonary artery to several vasoactive agents were determined by using in vitro vessel rings perfusion technique. Results：Compared with the control group, the contractile responses of pulmonary artery to potassium chloride （KCl,68M） and phenylephrine （ PE, 10^-9 - 10^-5 M） were markedly diminished after 14day tail-suspension, while the vasoactive responses to acetylcholine（ Ach, 10^-9- 10^-5M） were markedly enhanced. Conclusion： The contractile responsiveness is attenuated and the dilatory responsiveness is enhanced in the pulmonary arteries of rats after simulated weightlessness;impaired contractile responsiveness may contribute to orthostatic intolerance.