麻醉犬等长收缩运动中血浆一氧化氮浓度变化及其对血流动力学的影响

目的通过麻醉犬等长收缩运动(IE)中一氧化氮(NO)变化及与注入一氧化氮合成酶(NOS)抑制剂前后IE时心血管指标变化的比较,探讨NO对IE时血流动力学变化的调节作用.方法成年健康杂种犬14只,在安静、IE 3、6、9min,恢复5、10、20min时测定NO及各项血液动力学指标;然后注入NOS抑制剂,重复原试验,测各时间点血流动力学指标.结果IE时NO浓度下降,IE 9min时下降23.6% (P＜0.05),恢复期NO浓度水平逐渐恢复.IE 9min时心率上升明显(P＜0.05)而注入NOS抑制剂后IE 9min时HR下降明显(P＜0.05).收缩压、舒张压及肺毛细血管楔嵌压在注入NOS抑制剂后三者的净增量均高于注入前(P＜0.05).在注入NOS抑制剂后总肺循环阻力、肺动脉阻力、体循环血管阻力均明显上升(P＜0.05).结论急性运动时NO浓度水平下降;NO 不但可以降低外周血管阻力也可降低肺血管阻力,从而减轻IE时的心血管负荷.

Variation of nitric oxide and hemodynamic effect during isometric exercise on anaesthesia dogs

Objective:To observe the nitric oxide(NO) variation in isometric exercise(IE) and the hemodynamic effect before and after injected nitric oxide synthase (NOS) inhibitor on anasethesia dogs.Method: Fourteen adult dogs performed IE by farabism stimulation .NO and hemodynamic indexes were measured during the experiment.Result: NO decreased during IE(P<0.01). Heart rate increased(P<0.05) but decreaing by injecting NOS inhibitor(P<0.05) during isometric exercise. The net increase of blood pressure(BP),pulmonary capillary wedge pressure(PCWP) was higher than that before injecting NOS inhibitor (P<0.05).Total pulmonary resistance(TPR),pulmonary vascular resistance(PVR)and systemic vascular resistance(SVR) were increased after injected NOS inhibitor(P<0.05). Conclusion :NO decreases during acute exercise.NO can decrease cardiovascular load during IE through decreasing TPR and SVR.