一氧化氮对急、慢性缺氧大鼠血流动力学及缺氧性肺血管收缩反应的影响

观察了吸入０．００４％的一氧化氮（ＮＯ）对急、慢性缺氧大鼠血流动力学、缺氧性肺血管收缩反应（ＨＰＶ）、血气及高铁血红蛋白（ＭｅｔＨｂ）的影响。结果表明：（１）常氧吸入ＮＯ时能明显降低慢性缺氧大鼠肺动脉平均压（Ｐｐａ）和肺血管阻力（ＰＶＲ），但对正常大鼠的Ｐｐａ和ＰＶＲ无明显影响；（２）慢性缺氧大鼠急性缺氧时ＨＰＶ较正常大鼠弱，吸入ＮＯ不但降低两者的急性缺氧肺动脉高压，且完全逆转两者的ＨＰＶ；（３）吸入ＮＯ对急、慢性缺氧大鼠体循环血流动力学、血气及ＭｅｔＨｂ含量无明显影响。提示吸入ＮＯ能选择性降低，急、慢性缺氧性肺动脉高血压，且逆转ＨＰＶ。

Effects of Inhaled Nitric Oxide on Hemodynamics and Hypoxic Pulmonary Vasoconstriction in Acute and Chronic Hypoxic Rats

The effects of inhalation of 0.004% nitric oxide (NO) on hemodynamics, hypoxic pulmonary vasoconstriction (HPV), blood gas and plasma methemoglobin (MethBb) level in acute as well as chronic hypoxic rats were investigated.The results were as follows:(1)The mean pulmonary arterial pressure(Ppa)and pulmonary vascular resistance (PVR) were significantly decreased by inhaled NO in chronic hypoxic rats (P<0.01), but these changes were not observed in normoxic control ratst.(2)The HPV was weaker in chronic hypoxic rats than that in control animals. The pulmonary arterial hypertension induced by acute hypoxia was lowered greatly and HPV strengthened by acute hypoxia was reversed completely by inhalation of NO in both chronic hypoxic control rats. (3)There was no effect on systemic arterial pressure,systemic vascular resistance, PaO_2,P_aCO_2 and MetHb level in acute and chronic hypoxic rats inhaling NO. It is suggested that the pulmonary arterial hypertension induced by acute and chronic hypoxia could be lowered selectively and the HPV induced by hypoxia could be reversed by inhalation of 0. 004% NO in rats.