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首页> 外文期刊>American Journal of Physiology >Direct observation of epicardial coronary capillary hemodynamics during reactive hyperemia and during adenosine administration by intravital video microscopy.
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Direct observation of epicardial coronary capillary hemodynamics during reactive hyperemia and during adenosine administration by intravital video microscopy.

机译：通过活体视频显微镜直接观察反应性充血和腺苷给药期间心外膜冠状动脉毛细血管动力学。

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摘要

Using high-resolution intravital charge-coupled device video microscopy, we visualized the epicardial capillary network of the beating canine heart in vivo to elucidate its functional role under control conditions, during reactive hyperemia (RH), and during intracoronary adenosine administration. The pencil-lens video-microscope probe was placed over capillaries fed by the left anterior descending artery in atrioventricular-blocked hearts of open-chest, anesthetized dogs paced at 60-90 beats/min (n = 17). In individual capillaries under control conditions, red blood cell flow was predominant during systole or diastole, indicating that the watershed between diastolic arterial and systolic venous flows is located within the capillaries. Capillary flow increased during RH and reached a peak flow velocity (2.1 +/- 0.6 mm/s), twice as high as control (1.2 +/- 0.5 mm/s), with enhancement of intercapillary cross-connection flow and enlargement of diameter (by 17%). With adenosine, capillary flow velocity significantly increased (1.8 +/- 0.7 mm/s). However, the increase in volumetric capillary flow with adenosine estimated from red blood cell velocity and diameter was less than the increase in arterial flow, whereas that during RH was nearly equivalent to the increase in arterial flow. There was a time lag of approximately 1.5 s for refilling of capillaries during RH, indicating their function as capacitance vessels. In conclusion, the coronary capillary network functions as 1) the major watershed between diastolic-dominant arterial and systolic-dominant venous flows, 2) a capacitor, and 3) a significant local flow amplifier and homogenizer of blood supply during RH, but with adenosine the increase in capillary flow velocity was less than the increase in arterial flow.
机译：使用高分辨率的活体内电荷耦合装置视频显微镜，我们在体内观察了跳动犬心脏的心外膜毛细血管网络，以阐明其在控制条件下，反应性充血（RH）和冠状动脉内腺苷给药过程中的功能作用。将铅笔透镜的视频显微镜探头放在以60-90次/分钟（n = 17）的速度开胸，麻醉的狗的房室传导阻滞的心脏中，由左前降支支配的毛细血管上方。在对照条件下的单个毛细血管中，在收缩或舒张期红细胞流量占主导地位，这表明舒张动脉和收缩期静脉血流之间的分水岭位于毛细血管内。 RH期间毛细血管流量增加，达到峰值流速（2.1 +/- 0.6 mm / s），是对照的最高流速（1.2 +/- 0.5 mm / s）的两倍，同时增加了毛细血管间的交叉连接流量并增大了直径（降低了17％）。使用腺苷时，毛细血管流速显着增加（1.8 +/- 0.7 mm / s）。然而，根据红细胞速度和直径估计的腺苷体积毛细血管流量的增加少于动脉血流量的增加，而在RH期间，这几乎等于动脉血流量的增加。在RH期间重新填充毛细管大约有1.5 s的时间滞后，表明它们充当电容容器。总之，冠状动脉毛细血管网的功能是：1）舒张为主的动脉血流和收缩为主的静脉血流之间的主要分水岭; 2）电容器; 3）RH期间血液供应的重要局部流量放大器和均质器，但带有腺苷毛细血管流速的增加小于动脉血流的增加。

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