犬冠状动脉阻力的胆碱能调节

本实验在麻醉开胸犬,采用冠状动脉左旋支恒流灌注,于搏动的和心室纤颤(VF)的心脏,研究了电刺激迷走神经(VNS)及冠状动脉内注入乙酰胆碱(ACh)对冠状动脉阻力的影响。当 VNS 和冠脉内给 ACh 时,(1)心肌内小冠状动脉阻力显著减低,而心外膜大冠状动脉阻力并无明显变化;(2)冠状动脉左旋支总阻力的减低幅度在 VF 的心脏比在搏动的心脏显著减小。以上结果表明,迷走-ACh 扩张冠脉的作用主要是舒张心肌内小冠状动脉,并可通过减低心肌收缩力而间接降低冠状动脉阻力。

CHOLINERGIC CONTROL OF CORONARY RESISTANCE IN THE DOG

Effect of vagal stimulation(VNS)and intracoronary infusion of acetylcholine(ACh)on coronary resistance was studied in the beating and fibrillating heart withthe circumflex coronary artery being perfused at constant flow.Under the condi-tions of VNS and intracoronary ACh,(1)the resistance of myocardial coronary ar-teries decreased obviously without significant change in the resistance of epicardiallarge coronary arteries;(2)the extent of decrease in total resistance of the left circum-flex branch in the fibrillating heart was significantly less than that in the beatingheart.These results showed that the action of vagus and ACh on coronary arterieswas to dilate predominantly the myocardial small arteries,the resistance of whichwas further reduced indirectly through decreasing myocardial contractility.