Enhancement of mechanical performance in frog muscle fibres after quick increases in load.
Enhancement of mechanical performance in frog muscle fibres after quick increases in load.
复制标题
负荷快速增加后青蛙肌纤维的机械性能增强。
DOI：
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发表时间：
1981
期刊：
影响因子：
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通讯作者：
T. Tsuchiya
中科院分区：
文献类型：
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作者：
H. Sugi;T. Tsuchiya
1.青蛙骨骼肌纤维的能力，以维持负荷的变化进行了研究过程中的振荡长度变化或连续等张延长负荷快速增加后，通过应用“测试”负荷步骤和测量的初始速度产生的等张运动。2.当在振荡长度变化或连续等渗延长期间施加负荷快速降低时，发现纤维在高于最大张力（P0）的负荷下缩短，表明负荷快速增加后负荷维持能力增加。3.如果在先前快速增加负荷后的不同时间施加快速增加负荷，则所产生的等张延长的初始速度随时间而降低，也表明负荷维持能力增加。4.在1.6 - 1.7 P0的负荷下，在快速等张延长过程中也观察到负荷维持能力的增加，其中纤维随着速度的增加而延长。5.载荷快速增加后，载荷维持能力的增加与力-速度曲线向更高的力值移动有关，而在零载荷时，未观察到最大缩短速度的显著变化。6.通过测量与负荷步骤一致的快速长度变化来估计肌纤维的刚度。它随着等张载荷的降低而降低，当载荷趋于零时，接近某个有限值。对于低于P0的等张载荷，随着载荷趋于零，接近某一有限值。对于高于P0的等张载荷，当载荷逐步降低用于刚度测量时，刚度随着等张载荷的增加而增加，直至1.6 - 1.7 P0。7.在快速增加负荷后的纤维的机械性能的增强的机制进行了讨论有关的滑动丝/跨桥假设的肌肉收缩。
1. The change in the ability of frog skeletal muscle fibres to sustain a load was studied during the course of oscillatory length changes or continuous isotonic lengthening following quick increases in load, by applying "test’ load steps and measuring the initial velocity of resulting isotonic motion. 2. When quick decreases in load were applied during oscillatory length changes or continuous isotonic lengthening, the fibres were found to shorten against a load above the maximum tension (P0), indicating an increase in load‐sustaining ability after quick increases in load. 3. If quick increases in load were applied at various times after preceding quick increase in load, the initial velocity of resulting isotonic lengthening decreased with time, also indicating an increase in load‐sustaining ability. 4. An increase in load‐sustaining ability was also observed during the course of rapid isotonic lengthening under a load of 1.6‐1.7 P0, in which the fibres lengthened with increasing velocity. 5. The increase in load‐sustaining ability after quick increases in load was associated with a shift of the force‐velocity curve towards higher force values, while no significant change was observed in the maximum shortening velocity at zero load. 6. The stiffness of muscle fibres was estimated by measuring quick length changes coincident with load steps. It decreased with decreasing isotonic load below P0, approaching a certain finite value as the load tended to zero. For isotonic load below P0, approaching a certain finite value as the load tended to zero. For isotonic loads above P0, the stiffness increased with increasing isotonic load up to 1.6‐1.7 P0, when step decreases in load were used for stiffness measurements. 7. The mechanism of enhancement of mechanical performance of the fibres after quick increases in load is discussed in relation to the sliding filament/cross bridge hypotheses of muscle contraction.