REDUCED EFFECT OF PH ON SKINNED RABBIT PSOAS MUSCLE MECHANICS AT HIGH-TEMPERATURES - IMPLICATIONS FOR FATIGUE
REDUCED EFFECT OF PH ON SKINNED RABBIT PSOAS MUSCLE MECHANICS AT HIGH-TEMPERATURES - IMPLICATIONS FOR FATIGUE
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DOI：
10.1113/jphysiol.1995.sp020844
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发表时间：
1995-08-01
影响因子：
5.5
通讯作者：
COOKE, R
中科院分区：
文献类型：
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作者：
PATE, E;BHIMANI, M;COOKE, R
1.已经提出通过降低pH抑制肌动球蛋白功能来解释疲劳期间肌肉功能的大部分抑制。对这一假设的最有力的支持来自于对低温（小于或等于15摄氏度）下的剥皮骨骼肌纤维力学的研究。我们重新研究了pH值降低（7.0-6.2）对低温（10摄氏度）和高温（30摄氏度）下去皮哺乳动物骨骼纤维力学的影响，使用最近开发的协议，允许在更高的温度下获得可重复的力学数据。在10 ℃时，我们重复了先前的观察结果，即酸中毒显著抑制了最大缩短速度（V-max）和等长张力（P-0）。相反，在较高的温度下，我们发现酸中毒对V-max的影响非常小，而P-o的下降减少了三倍。因此，在温度仅略低于哺乳动物骨骼肌系统的生理，pH值在肌肉疲劳的过程中，在横桥水平的重要性要小得多的作用比已经建议的数据在生理上不切实际的温度。
1. Inhibition of actomyosin function by decreased pH has been proposed to account for much of the depression of muscle function during fatigue. The dearest support for this hypothesis has been from studies of skinned skeletal muscle fibre mechanics at low temperatures (less than or equal to 15 degrees C).2. We re-examined the effect of decreased pH (7.0-6.2) on skinned mammalian skeletal fibre mechanics at low (10 degrees C) and high (30 degrees C) temperatures, using recently developed protocols that allow reproducible mechanical data to be obtained at higher temperatures.3. At 10 degrees C we duplicated previous observations of a significant inhibition of maximum shortening velocity (V-max) and isometric tension (P-0) by acidosis. In contrast, at the higher temperature, we found only a very minimal effect of acidosis on V-max and a threefold reduction in the decrease in P-o.4. Thus at temperatures only slightly below physiological for mammalian skeletal muscle systems, pH plays a much less important role in the process of muscle fatigue at the crossbridge level than has been suggested by data obtained at physiologically unrealistic temperatures.