Egashira K, Katsuda Y, Mohri M, Kuga T, Tagawa T, Kubota T, Hirakawa Y, Takeshita A
Research Institute of Angiocardiology, Faculty of Medicine, Kyushu University, Fukuoka, Japan.
Circ Res. 1996 Aug;79(2):331-5. doi: 10.1161/01.res.79.2.331.
Endothelium-derived NO contributes to the control of coronary perfusion. We investigated the roles of NO in the metabolic coronary vasodilatation induced by rapid pacing in humans. We evaluated the dilatation of large epicardial and resistance coronary arteries during rapid atrial pacing before and after intracoronary infusion of NG-monomethyl-L-arginine (L-NMMA), an inhibitor of NO synthesis, in 19 patients without significant coronary artery disease. The diameter of the large epicardial coronary artery and coronary blood flow (CBF) were assessed by quantitative coronary arteriography and by a Doppler flow velocity measurement. An increase in the heart rate increased CBF (P < .01) and the coronary artery diameter (P < .05). L-NMMA at a total dose of 200 mumol reduced basal CBF but did not significantly affect basal coronary artery diameter, arterial pressure, or heart rate. L-NMMA inhibited the pacing-induced dilatation of the large coronary arteries (P < .05) but did not affect pacing-induced increases in CBF. L-NMMA inhibited the acetylcholine-induced increase in CBF (P < .01) and acetylcholine-induced dilatation of the large epicardial coronary artery (P < .05). These results show that the contribution of NO to the metabolic vasodilatation during rapid pacing may differ between large epicardial and resistance coronary arteries in patients without significant coronary artery disease.
内皮衍生的一氧化氮有助于控制冠状动脉灌注。我们研究了一氧化氮在人类快速起搏诱导的代谢性冠状动脉血管舒张中的作用。在19例无明显冠状动脉疾病的患者中，我们评估了在冠状动脉内注入一氧化氮合成抑制剂NG-单甲基-L-精氨酸（L-NMMA）前后快速心房起搏期间大的心外膜冠状动脉和阻力冠状动脉的舒张情况。通过定量冠状动脉造影和多普勒血流速度测量评估大的心外膜冠状动脉直径和冠状动脉血流量（CBF）。心率增加使CBF增加（P <.01），冠状动脉直径增加（P <.05）。总剂量为200 μmol的L-NMMA降低了基础CBF，但对基础冠状动脉直径﹑动脉血压或心率无显著影响。L-NMMA抑制了起搏诱导的大冠状动脉舒张（P <.05），但不影响起搏诱导的CBF增加。L-NMMA抑制了乙酰胆碱诱导的CBF增加（P <.01）和乙酰胆碱诱导的大的心外膜冠状动脉舒张（P <.05）。这些结果表明，在无明显冠状动脉疾病的患者中，一氧化氮对快速起搏期间代谢性血管舒张的作用在大的心外膜冠状动脉和阻力冠状动脉之间可能有所不同。
