Feigl E O, Buffington C W, Nathan H J
Circulation. 1987 Jan;75(1 Pt 2):I1-5.
The effects of adrenergic alpha-receptor-mediated coronary vasoconstriction were examined in the presence of coronary stenosis and during experimental coronary hypoperfusion. Adrenergic coronary vasoconstriction was observed to operate even in the presence of coronary stenosis to limit oxygen delivery to the heart and increase myocardial oxygen extraction, but this vasoconstrictor effect did not result in myocardial lactate production. During constant coronary pressure perfusion the transmural distribution of alpha-receptor coronary vasoconstriction was determined with microspheres. A uniform transmural distribution of alpha-receptor-mediated vasoconstriction was observed at normal and subnormal perfusion pressures. During constant flow hypoperfusion, which permits transmural coronary steal, the left ventricular inner/outer blood flow ratio was more favorable with alpha-receptors intact than with alpha-receptors blocked. These findings indicate that alpha-receptor-mediated coronary vasoconstriction has an unexpected beneficial effect by lessening transmural steal during coronary hypoperfusion.
在存在冠状动脉狭窄和实验性冠状动脉灌注不足的情况下，研究了肾上腺素能α受体介导的冠状动脉血管收缩的影响。即使存在冠状动脉狭窄，也观察到肾上腺素能冠状动脉血管收缩会限制心脏的氧气供应并增加心肌氧摄取，但这种血管收缩作用并未导致心肌乳酸生成。在恒定冠状动脉压力灌注期间，用微球测定α受体冠状动脉血管收缩的跨壁分布。在正常和低于正常灌注压力下，观察到α受体介导的血管收缩呈均匀的跨壁分布。在允许跨壁冠状动脉窃血的恒定流量灌注不足期间，α受体完整时左心室内/外血流比优于α受体阻断时。这些发现表明，α受体介导的冠状动脉血管收缩通过减少冠状动脉灌注不足期间的跨壁窃血具有意想不到的有益作用。
