Exercise training increases basal tone in arterioles distal to chronic coronary occlusion
Exercise training increases basal tone in arterioles distal to chronic coronary occlusion
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DOI：
10.1152/ajpheart.00973.2005
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发表时间：
2006-03-01
影响因子：
4.8
通讯作者：
Parker, JL
中科院分区：
文献类型：
--
作者：
Heaps, CL;Mattox, ML;Parker, JL
耐力运动训练增加了对照组动物冠状动脉的基础活动张力和增强了冠状动脉微动脉的肌源性张力。矛盾的是，运动训练也被证明增加了一氧化氮的产生和一氧化氮介导的冠状动脉小动脉的松弛。本研究的目的是观察运动训练对慢性冠脉闭塞心脏侧支依赖区小动脉基础活动张力的影响。在小型猪左回旋支冠状动脉近端放置美式封堵器。从静坐(围栏限制)和运动训练(跑步机跑步；14wk)的猪的侧支依赖和非闭塞心肌区域分离小动脉。使用微血管肌图和标准等长技术研究了分离小动脉的冠脉张力。暴露于名义上无钙离子的外部溶液降低了所有小动脉的静息张力；在运动训练动物的侧支依赖区域的小动脉中，降幅最大(P<；0.05)。此外，抑制一氧化氮合酶(N-pi-硝基-(L)-精氨酸甲酯；100muM)可显著增加运动训练猪侧支依赖区小动脉的一氧化氮敏感张力。阻断K+通道显示运动训练猪的侧支依赖小动脉中K+通道对基础张力的贡献显著增加。免疫印迹法检测运动组小动脉内皮型一氧化氮合酶(ENOS)和磷酸化eNOS(PS1179)的蛋白含量升高，对侧支依赖血管形成的影响最大。综上所述，我们证明了在慢性冠脉闭塞中，相反的运动训练增强了小动脉基础活动张力、一氧化氮的产生和K+通道活性的相互作用，潜在地增强了调节流向侧支依赖心肌的血流的能力。
Endurance exercise training increases basal active tone in coronary arteries and enhances myogenic tone in coronary arterioles of control animals. Paradoxically, exercise training has also been shown to augment nitric oxide production and nitric oxide-mediated relaxation in coronary arterioles. The purpose of the present study was to examine the effect of exercise training on basal active tone of arterioles (similar to 150 mu m ID) isolated from the collateral-dependent region of hearts exposed to chronic coronary occlusion. Ameroid occluders were surgically placed around the proximal left circumflex coronary artery of miniature swine. Arterioles were isolated from both the collateral-dependent and nonoccluded myocardial regions of sedentary (pen confined) and exercise-trained (treadmill run; 14 wk) pigs. Coronary tone was studied in isolated arterioles using microvessel myographs and standard isometric techniques. Exposure to nominally Ca2+-free external solution reduced resting tension in all arterioles; decreases were most profound (P < 0.05) in arterioles from the collateral-dependent region of exercise-trained animals. Furthermore, nitric oxide synthase (NOS) inhibition (N-pi-nitro-(L)-arginine methyl ester; 100 mu M) unmasked markedly increased nitric oxide-sensitive tone in arterioles from the collateral-dependent region of exercise-trained swine. Blockade of K+ channels revealed significantly enhanced K+ channel contribution to basal tone in collateral-dependent arterioles of exercise-trained pigs. Protein content of endothelial NOS (eNOS) and phosphorylated eNOS (pS1179), determined by immunoblot, was elevated in arterioles from exercise-trained animals with the greatest effect in collateral-dependent vasculature. Taken together, we demonstrate the interaction of opposing exercise training-enhanced arteriolar basal active tone, nitric oxide production, and K+ channel activity in chronic coronary occlusion, potentially enhancing the capacity to regulate blood flow to collateral-dependent myocardium.