Wright L, Homans D C, Laxson D D, Dai X Z, Bache R J
Department of Medicine, University of Minnesota Medical School, Minneapolis.
J Am Coll Cardiol. 1992 Mar 1;19(3):687-93. doi: 10.1016/s0735-1097(10)80293-1.
This study was performed to determine whether thromboxane A2 (as the analogue U46619) and serotonin can cause vasoconstriction of moderately well developed coronary collateral vessels. Studies were carried out in seven adult mongrel dogs 2 to 4 months after embolic occlusion of the left anterior descending coronary artery had been performed to stimulate collateral vessel growth. At the time of study this artery was cannulated to determine interarterial collateral flow from measurements of retrograde blood flow. Radioactive microspheres were administered during retrograde flow collection to determine continuing tissue flow for evaluation of microvascular collateral communications. Serotonin (50 micrograms/min) resulted in a 48 +/- 11% decrease in retrograde flow (p less than 0.01), with a 36 +/- 10% decrease in total collateral blood flow (p less than 0.02). Infusion of U46619 (0.01 microgram/kg per min) caused a 38 +/- 13% decrease in retrograde blood flow (p less than 0.01), with a 34 +/- 13% decrease in total collateral flow (p less than 0.05). Serotonin caused a significant increase in tissue flow to the subepicardium of the collateral-dependent region, whereas U46619 caused no change in tissue blood flow. These data demonstrate that both serotonin and thromboxane A2 can cause vasoconstriction of interarterial coronary collateral vessels. The findings suggest that platelet activation in coronary arteries from which collateral vessels originate has potential for causing collateral vasoconstriction, thereby compromising blood flow to the dependent myocardium.
本研究旨在确定血栓素A2（作为类似物U46619）和5-羟色胺是否会引起中等程度发育良好的冠状动脉侧支血管收缩。研究在7只成年杂种犬身上进行，这些犬在左前降支冠状动脉栓塞闭塞2至4个月后进行，以刺激侧支血管生长。在研究时，将该动脉插管，通过测量逆行血流来确定动脉间侧支血流。在收集逆行血流期间给予放射性微球，以确定持续的组织血流，用于评估微血管侧支循环。5-羟色胺（50微克/分钟）使逆行血流减少48±11%（p<0.01），总侧支血流减少36±10%（p<0.02）。输注U46619（0.01微克/千克每分钟）使逆行血流减少38±13%（p<0.01），总侧支血流减少34±13%（p<0.05）。5-羟色胺使侧支依赖区域的心外膜下组织血流显著增加，而U46619对组织血流无影响。这些数据表明，5-羟色胺和血栓素A2均可引起冠状动脉间侧支血管收缩。这些发现提示，侧支血管起源的冠状动脉中的血小板激活有可能导致侧支血管收缩，从而损害对依赖心肌的血流供应。
