Akazawa K, Yamamoto M, Fujii K, Mashima H
Jpn J Physiol. 1976;26(1):9-28. doi: 10.2170/jjphysiol.26.9.
A mechanochemical model for muscle contraction was presented which consisted of three subsystems: the regulatory mechanism of contraction by Ca ion, the cross-bridge cycle coupled with actin-myosin interaction and the dynamics of contraction with an external load. It was assumed that both the rate constant of the cross-bridge cycle and the net force of the cross-bridge were linear functions of the sliding velocity. Most parameters in the model were determined from the experimental data, but several were estimated by simulation techniques. The model adequately described the force-load-velocity relation, the rates of energy and heat output as well as some basic mechanical properties of muscle. Not only the steady-state contraction but also the twitch response could be explained by the model. Time courses of tension and shortening during isometric and isotonic twitches were calculated by the model on a digital computer. The calculated curves agreed satisfactorily with the experimental ones obtained from the frog semitendinosus muscle. The rate of tension rise of the isometric twitch was shown to attain the peak at nearly the same time as does the calculated Ca concentration curve.
提出了一种肌肉收缩的机械化学模型，该模型由三个子系统组成：钙离子对收缩的调节机制、与肌动蛋白-肌球蛋白相互作用相关的横桥循环以及有外部负载时的收缩动力学。假定横桥循环的速率常数和横桥的净力均为滑动速度的线性函数。模型中的大多数参数由实验数据确定，但有几个是通过模拟技术估算的。该模型充分描述了力-负载-速度关系、能量和热量输出速率以及肌肉的一些基本力学特性。该模型不仅可以解释稳态收缩，还能解释抽搐反应。通过该模型在数字计算机上计算了等长和等张抽搐过程中张力和缩短的时间进程。计算曲线与从青蛙半腱肌获得的实验曲线吻合良好。结果表明，等长抽搐的张力上升速率在几乎与计算得到的钙浓度曲线相同的时间达到峰值。
