Perfusion-induced changes in cardiac contractility depend on capillary perfusion
Perfusion-induced changes in cardiac contractility depend on capillary perfusion
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DOI：
10.1152/ajpheart.1998.274.2.h405
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发表时间：
1998-02-01
影响因子：
4.8
通讯作者：
Westerhof, N
中科院分区：
文献类型：
--
作者：
Dijkman, MA;Heslinga, JW;Westerhof, N
灌注引起的心肌收缩力增加（格雷格现象）尤其出现在缺乏足够的冠状动脉自动调节从而保护毛细血管压力变化的心脏制剂中。我们在大鼠的分离灌注乳头肌中确定心肌收缩力是否与毛细血管灌注相关。该肌肉的氧气利用率独立于内部灌注，并且灌注可以改变甚至停止而不丧失功能。肌肉在 27 摄氏度时等长收缩 (n = 7)。在控制状态期间，灌注压的逐步增加导致所有肌肉的主动张力显着增加。肌肉直径总是随着灌注压的增加而增加，但肌肉段的长度不受影响。然后用塑料微球(15μm)阻碍毛细血管灌注。在66.6+/-26.2cmH(2)O的灌注压力下，流量从对照状态下的17.6+/-5.4μl/min减少至微球后的3.2+/-1.3μl/min。在微球之前和微球之后，在未灌注条件下由肌肉产生的主动张力没有显着差异（-12.8+/-29.4%变化）。在微球后，与对照类似的灌注压力步骤从未导致主动张力增加。即使在施加的两个最高灌注压力（89.1+/-28.4和106.5+/-31.7cmH(2)O）下，也发现主动张力显着降低。我们得出结论，格雷格现象与毛细血管灌注有关。
The perfusion-induced increase in cardiac contractility (Gregg phenomenon) is especially found in heart preparations that lack adequate coronary autoregulation and thus protection of changes in capillary pressure. We determined in the isolated perfused papillary muscle of the rat whether cardiac muscle contractility is related to capillary perfusion. Oxygen availability of this muscle is independent of internal perfusion, and perfusion may be varied or even stopped without loss of function. Muscles contracted isometrically at 27 degrees C (n = 7). During the control state stepwise increases in perfusion pressure resulted in all muscles in a significant increase in active tension. Muscle diameter always increased with increased perfusion pressure, but muscle segment length was unaffected. Capillary perfusion was then obstructed by plastic microspheres (15 mu m). Flow, at a perfusion pressure of 66.6 +/- 26.2 cmH(2)O, reduced from 17.6 +/- 5.4 mu l/min in the control state to 3.2 +/- 1.3 mu l/min after microspheres. Active tension developed by the muscle in the unperfused condition before microspheres and after microspheres did not differ significantly (-12.8 +/- 29.4% change). After microspheres similar perfusion pressure steps as in control never resulted in an increase in active tension. Even at the two highest perfusion pressures (89.1 +/- 28.4 and 106.5 +/- 31.7 cmH(2)O) that were applied a significant decrease in active tension was found. We conclude that the Gregg phenomenon is related to capillary perfusion.