Parent R, Paré R, Lavallée M
Department of Physiology, University of Montreal, Quebec, Canada.
Am J Physiol. 1992 Jan;262(1 Pt 2):H10-6. doi: 10.1152/ajpheart.1992.262.1.H10.
Endothelium-dependent relaxation of conductance coronary vessels involves nitric oxide formation from L-arginine. The present study examines whether a similar mechanism intervenes in the vasomotor control of resistance coronary vessels. In conscious dogs, the excess of coronary blood flow (CBF) created by intracoronary acetylcholine (3.0 ng/kg) averaged 7.2 +/- 1.1 ml. Intracoronary adenosine (100 ng/kg) increased CBF by 12.4 +/- 1.4 ml. Intracoronary nitroglycerin (175 ng/kg) increased CBF by 7.4 +/- 1.2 ml. CBF repayment-to-debt ratio after a 15-s coronary arterial occlusion averaged 2.8 +/- 0.2. After an intracoronary N omega-nitro-L-arginine dose (10 micrograms.kg-1.min-1 x 12 min) was given to inhibit nitric oxide formation, baseline CBF was not altered. CBF increases with acetylcholine averaged 2.4 +/- 0.5 and 6.4 +/- 0.7 ml with adenosine, both less (P less than 0.01) than responses before the arginine analogue. CBF increases with nitroglycerin averaged 7.2 +/- 1.1 ml, similar to control responses. CBF repayment-to-debt ratio during reactive hyperemic responses fell (P less than 0.01) to 1.7 +/- 0.1. L-Arginine (1.0 mg.kg-1.min-1 x 12 min) partially reversed the inhibitory effect of the arginine analogue on CBF responses to acetylcholine. Thus nitric oxide formed in resistance coronary vessels is a major mediator of coronary vasodilation to acetylcholine, adenosine and transient ischemia.
传导性冠状动脉血管的内皮依赖性舒张涉及由L-精氨酸生成一氧化氮。本研究探讨是否有类似机制参与阻力性冠状动脉血管的血管舒缩控制。在清醒犬中，冠状动脉内注入乙酰胆碱（3.0 ng/kg）所产生的冠状动脉血流量（CBF）过量平均为7.2±1.1 ml。冠状动脉内注入腺苷（100 ng/kg）使CBF增加12.4±1.4 ml。冠状动脉内注入硝酸甘油（175 ng/kg）使CBF增加7.4±1.2 ml。15秒冠状动脉闭塞后的CBF偿还-债务比平均为2.8±0.2。给予冠状动脉内Nω-硝基-L-精氨酸剂量（10 μg·kg-1·min-1×12分钟）以抑制一氧化氮生成后，基础CBF未改变。乙酰胆碱使CBF增加平均为2.4±0.5 ml，腺苷使CBF增加平均为6.4±0.7 ml，两者均低于（P＜0.01）精氨酸类似物给药前的反应。硝酸甘油使CBF增加平均为7.2±1.1 ml，与对照反应相似。反应性充血反应期间的CBF偿还-债务比降至（P＜0.01）1.7±0.1。L-精氨酸（1.0 mg·kg-1·min-1×12分钟）部分逆转了精氨酸类似物对CBF对乙酰胆碱反应的抑制作用。因此，阻力性冠状动脉血管中形成的一氧化氮是冠状动脉对乙酰胆碱、腺苷和短暂性缺血舒张反应的主要介质。
