高原适应动物牦牛与普通黄牛肺血管反应性的比较研究

Comparative study of the responsiveness of pulmonary artery between yaks and cows

本文应用张力测定方法观察了高原适应动物─－牦牛和普通黄牛肺内动脉血管条对缩血管物质的反应性，并观察两者在乙酰胆碱内皮依赖性舒张反应中的差异。结果显示，体重相近的牦牛和黄牛，其肺内动脉血管条对去甲肾上腺素（ＮＥ）的收缩强度明显不同，当ＮＥ为１０￣－７ｍｏｌ／Ｌ时，黄牛肺血管条收缩张力为１２６１±２０１ｍｇ，而牦牛仅为７４７±１００ｍｇ，两者差异显著（Ｐ＜０．０１）。内皮细胞完整的黄牛和牦牛肺动脉血管条对乙酰胆碱（Ａｃｈ）均表现出浓度依赖性舒张反应，其中牦牛的舒张作用更明显，在Ａｃｈ浓度分别为１０￣－８，１０￣－７，１０￣－６，１０￣－５ｍｏｌ／Ｌ时，牦牛肺血管条分别舒张：２８．３％，４２．６％，５２．８％，６５．３％，而黄牛仅为：４．３％，１６．４％，２３．２％，３４．８％，各相应Ａｃｈ浓度间的差异均Ｐ＜０．０１。去除内皮细胞后，黄牛和牦牛的肺动脉血管条对Ａｃｈ的舒张反应均消失。研究表明，黄牛肺动脉对缩血管物质更敏感，而牦牛肺动脉对舒血管物质反应更明显。其间的差异很可能构成了高原适应动物动脉压不高的生理基础。

The experiment was designed to investigate the pulmonary vascular respon- siveness(PVR)of yaks[at Qinhai-Tibet plateau(3500～4500m)]and migrated cows[at Xinin(2260m)]to norepinephrine(NE),and the difference in endothelium-dependent relaxation response to acetylcholine (Ach)between these two species.The strips of intrapulmonary artery(IPPA)were suspended in an organ bath containing Krebs solution at 37℃.The results showed that the tension of IPPA strips from cows(n=7)was higher than that from yaks(n=7)after 10￣-7mol/L NE challenge.The strips with intact endothelium fromboth cows and yaks showed concentration──dependent relaxation to Ach,which was moremarked in yaks.After removal of endothelium,relaxation in both yaks and cows dis-appeared.The pulmonary artery of yak seems to have lower sensitivity to vasoconstrictorsand stronger response to vasodilation than cow does.