Force generation and temperature-jump and length-jump tension transients in muscle fibers.
Force generation and temperature-jump and length-jump tension transients in muscle fibers.
复制标题
肌纤维中的力产生以及温度跳跃和长度跳跃张力瞬变。
DOI：
10.1016/s0006-3495(95)80380-2
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发表时间：
1995
期刊：
影响因子：
--
通讯作者：
Rodgers,ME
中科院分区：
文献类型：
--
作者：
Davis,JS;Rodgers,ME
肌肉张力随着温度升高而升高。在激光跳温实验中，对控制最大 Ca(2+) 激活、剥皮兔腰肌纤维在 0-30 摄氏度温度范围内张力上升的动力学进行了表征。动力学响应很简单，可以很容易地用收缩的基本三步机制来解释，其中包括与温度不敏感的限速步骤相关的温度敏感的快速预平衡(a)，以及随后的温度敏感的张力产生步骤。这些数据和机制与更复杂的长度跳跃赫胥黎-西蒙斯阶段进行了比较和对比，在该阶段中，所有产生张力或承受张力的状态都受到扰动。 Huxley-Simmons 相 4 的速率在低温下对温度敏感，但在高温下趋于平稳，表明限速步骤从温度敏感（相 4a）到温度不敏感反应（相 4b）的变化；后者似乎与缓慢的、对温度不敏感的温跃弛豫有关。温度跳跃中不存在第 3 阶段，这使其无法产生张力。我们证实，从头产生张力是在第 2slow 阶段和等效的温度敏感温度跳跃弛豫过程中作为有序-无序转变发生的。
Muscle tension rises with increasing temperature. The kinetics that govern the tension rise of maximally Ca(2+)-activated, skinned rabbit psoas fibers over a temperature range of 0–30 degrees C was characterized in laser temperature-jump experiments. The kinetic response is simple and can be readily interpreted in terms of a basic three-step mechanism of contraction, which includes a temperature-sensitive rapid preequilibrium(a) linked to a temperature-insensitive rate-limiting step and followed by a temperature-sensitive tension-generating step. These data and mechanism are compared and contrasted with the more complex length-jump Huxley-Simmons phases in which all states that generate tension or bear tension are perturbed. The rate of the Huxley-Simmons phase 4 is temperature sensitive at low temperatures but plateaus at high temperatures, indicating a change in rate-limiting step from a temperature-sensitive (phase 4a) to a temperature-insensitive reaction (phase 4b); the latter appears to correlate with the slow, temperature-insensitive temperature-jump relaxation. Phase 3 is absent in the temperature-jump, which excludes it from tension generation. We confirm that de novo tension generation occurs as an order-disorder transition during phase 2slow and the equivalent, temperature-sensitive temperature-jump relaxation.