过氧亚硝基阴离子诱导离体兔肺动脉舒张反应的特性

实验用离体血管环张力测定技术,观察过氧亚硝基阴离子（ONOO）对离体预收缩的兔肺动脉的舒张反应、肺动脉内皮细胞对舒张反应的影响,并初步探讨其病理意义。结果显示,ONOO可剂量依赖性引起预收缩兔肺动脉舒张。分解的ONOO也有舒张作用,但其效应明显低于ONOO的作用,比较观察表明,ONOO的舒张效应显著低于硝普钠（SNP）和乙酰胆碱（ACh)。与内皮完整2的肺动脉比较,ONOO对去内皮肺动脉的舒张作用明显增加,剂量依赖性舒张反应曲线明显左移。肺动脉对ONOO重复作用时的舒张反应有递减趋势。在本实验条件下,ONOO舒张前后的肺动脉,对ACh的舒张反应无明差异。结果表明,ONOO对肺动脉的舒张作用较弱,此作用受到内皮细胞的抑制性调节并有快速去敏性。

Properties of peroxynitrite-induced relaxation in rabbit pulmonary artery in vitro

Vasodilatory properties of exogenous peroxynitrite (ONOO ) and effects of endothelial cells on ONOO induced relaxation were investigated in isolated rabbit pulmonary arterial rings (PARs). In pre contracted PARs, ONOO gave rise to vasodilation in a dose dependent manner, which was significantly higher than that of decomposed ONOO . In contrast, relaxation of PARs to ONOO was lower, as compared with sodium nitroprusside (SNP) or acetylcholine(ACh). ONOO induced more significan relaxation in denuded endothelial PARs than in intact endothelial PARs. Relaxation of PARs to repetitively administered ONOO appeared progressively decreased. Under this experimental condition, relaxation of PARs to ACh remained unchanged after administrating ONOO . These results suggest that ONOO causes weak relaxation in pulmonary artery, which is down regulated by endothelium and is of tachyphylaxis.