心肌局部缺氧引起冠状动脉扩张的实验研究

Mechanism of coronary vasodilation in myocardial regional hypoxia

目的探讨心肌局部缺氧引起冠状动脉扩张作用与交感神经受体完整性的关系。方法应用冠状动脉灌注系统，制备心肌局部缺氧模型，观察了１０只犬在缺氧环境下，冠状动脉血流变化；交感神经受体阻滞剂对心肌局部缺氧引起冠状动脉血流变化的影响。结果应用交感神经受体阻滞剂前，低氧血冠状动脉灌注时各项血流动力学指标与常氧血冠状动脉灌注时比较，冠状动脉血流增加了２２５％；应用交感神经受体阻滞剂后，无论是否冠状动脉低氧血灌注，左心室压力上升速度（ｄｐ／ｄｔｍａｘ，ｄｐ／ｄｔｍｉｎ）与用药前比较差异均有显著性意义。但低氧血灌注时，冠状动脉血流增加１９０％。

Objective To determine if coronary vasodilation is dependent upon adrenergic activation during myocardial regional. Methods Studies were conducted in 10 Mongrel dogs of either sexes, in which LAD was perfused with normoxic (CAO2=18.4～20.4 ml/100ml) or regional hypoxic (CAO 2=7.8～8.1 ml/100 ml) blood with coronary perfusion system by self control methods. Results No significant differences were observed in hemodynamic values with regional hypoxia compared with normoxia before adrenergic receptor blocker was given, but coronary blood flow increased by 225%. There were significant differences in dp/dt max, dp/dt min after adrenergic blocker was given. Whether there was regional hypoxia or not, coronary blood flow still increased by190%. Conclusion Coronary vasodilation is independent upon adrenergic activation during myocardial regional hypoxia.