Griffiths P J, Güth K, Kuhn H J, Rüegg J C
Biophys Struct Mech. 1980;7(2):107-24. doi: 10.1007/BF00538402.
Mechanically skinned single fibres of the semitendinosus muscles of Rana esculenta were investigated at ca. 4 degrees C. The fibres were activated by a Ca2+ jump technique, which allowed the development of a steady isometric tension within several seconds of entering a calcium rich solution at 4 degrees C. Sequences of length changes of different duration and amplitude were applied to the fibre. It could be demonstrated that the fibre behaved as a Hookean spring in the case of small amplitude length changes (up to 0.5% L0, ramp duration 0.5 ms) and that a sequence of length changes induced reversible changes in fibre state. In contrast, large stretches (greater than 1% L0) induced a muscle "give" if the stretch were not immediately preceded by a release. The data was interpreted on the basis of a strain induced detachment of cross bridges in combination with a rapid reattachment of presumably the same cross bridges in a discharged position. The rates of strain induced detachment and reattachment depended on the stretch amplitude. At amplitudes exceeding 2% L0 the rates were estimated to be at least several thousands per second.
在约4摄氏度的条件下，对食用蛙半腱肌的机械去膜单纤维进行了研究。纤维通过Ca2+跳跃技术激活，该技术使得在4摄氏度下进入富含钙的溶液后的几秒钟内就能产生稳定的等长张力。向纤维施加了不同持续时间和幅度的长度变化序列。结果表明，在小幅度长度变化（高达0.5%L0，斜坡持续时间0.5毫秒）的情况下，纤维表现为胡克弹簧，并且一系列长度变化会引起纤维状态的可逆变化。相比之下，如果拉伸之前没有立即进行释放，大的拉伸（大于1%L0）会导致肌肉“屈服”。这些数据是基于应变诱导的横桥脱离，并结合推测在卸载位置的相同横桥的快速重新附着来解释的。应变诱导的脱离和重新附着的速率取决于拉伸幅度。在幅度超过2%L0时，速率估计至少为每秒数千次。
