Persistent coronary vasodilation during long-term, supramaximal doses of adenosine.
Persistent coronary vasodilation during long-term, supramaximal doses of adenosine.
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长期、超最大剂量腺苷期间持续冠状血管舒张。
DOI：
10.1152/ajpheart.1984.247.5.h869
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发表时间：
1984
期刊：
影响因子：
--
通讯作者：
Bashour,FA
中科院分区：
文献类型：
--
作者：
Crystal,GJ;Downey,HF;Bashour,FA
主动和反应性充血已观察到骨骼肌循环快速外源性腺苷3小时超大剂量的血管扩张剂。这些发现未能支持腺苷在骨骼肌血流代谢控制中的需要。本研究旨在确定冠状动脉循环是否也对腺苷产生快速耐受，同时对其他代谢相关的血管扩张机制保持敏感。实验在8只戊巴比妥麻醉开胸犬中进行，其左前降支冠状动脉（LAD）中的血流量在3小时的腺苷输注到LAD期间被电磁测量。还测量了局部心肌血流量（放射性微球）、心肌耗氧量（菲克原理）和节段缩短百分比（超声晶体）。腺苷以27.0-72.0 mumol/min的速率输注到LAD中，这取决于血液流速。计算出的LAD血液中腺苷浓度平均为0.484 +/- 0.111 mumol/ml，这远远超过了最大冠状血管舒张所需的浓度。在腺苷前对照条件下，LAD血流平均为21.5 +/- 2.2 ml/min。腺苷3小时后的LAD血流量（123.3 +/- 23.0 ml/min）与腺苷1-3分钟后的LAD血流量（105.8 +/- 17.9 ml/min）无显著差异。在腺苷输注过程中，LAD血流无明显的跨壁变化。腺苷对心肌耗氧量或心肌节段缩短率无显著影响。我们的研究结果表明，在犬冠状动脉循环中，在长期的，超最大剂量的腺苷持续的透壁血管舒张，并与内源性腺苷在心肌能量需求持续升高期间维持冠状动脉血管舒张的作用一致。
Active and reactive hyperemias have been observed in the skeletal muscle circulation tachyphylactic to exogenous adenosine following 3-h supramaximal doses of the vasodilator. These findings failed to support a need for adenosine in metabolic control of skeletal muscle blood flow. The present study was conducted to determine if the coronary circulation also develops tachyphylaxis to adenosine while remaining sensitive to other metabolically linked vasodilator mechanisms. Experiments were conducted in eight pentobarbital-anesthetized, open-chest dogs whose blood flow in the left anterior descending coronary artery (LAD) was measured electromagnetically during 3-h infusion of adenosine into the LAD. Measurements of regional myocardial blood flow (radioactive microspheres), myocardial O2 consumption (Fick principle), and percent segment shortening (ultrasonic crystals) were also obtained. Adenosine was infused into the LAD at a rate of 27.0-72.0 mumol/min, depending on blood flow rate. Calculated concentration of adenosine in LAD blood averaged 0.484 +/- 0.111 mumol/ml, which was well in excess of that required for maximal coronary vasodilation. LAD blood flow averaged 21.5 +/- 2.2 ml/min during the preadenosine control condition. LAD blood flow after 3 h adenosine (123.3 +/- 23.0 ml/min) was not significantly different from that after 1-3 min adenosine (105.8 +/- 17.9 ml/min). There was no significant transmural variation in LAD blood flow during adenosine infusion. Adenosine had no significant effect on myocardial O2 consumption or percent segment shortening. Our results demonstrate persistent transmural vasodilation in the canine coronary circulation during long-term, supramaximal doses of adenosine and are consistent with a role for endogenous adenosine in maintenance of coronary vasodilation during sustained elevations in myocardial energy demands.