肌肉收缩中横桥间的协作行为(英文)

Cooperative Behaviors of Cross-Bridges in Muscle Contraction

根据横桥模型,肌肉中的横桥分子对细纤丝的周期性作功导致肌肉收缩,研究了在一维情况下,肌肉等张收缩(即外界的负荷F是常量)时,其横桥分子间的两种协作行为。首先,假设了单个横桥分子在作功过程中的能量与时间关系。在此基础上,考察了横桥分子间的两种协作行为:(1 )n0 个处于接触状态的横桥分子同步的工作,其作功过程与外界影响无关;(2 )n0 个处于接触状态的横桥分子同步的工作,但它们作功的频率正比于细纤丝在肌肉收缩中的速率V。计算了这两种假设情况下肌肉的外界负荷F与其收缩速率V的关系。发现,在第一种情况下,F V的关系曲线形状上类似于实验上得到的希尔曲线;在第二种情况下,肌肉收缩的速率V反比于外界负荷F。

According to swinging cross bridge model,muscle contraction is produced by cyclical attachment and detachment of cross bridges towards thin filament. The cooperative behaviors of cross bridges in muscle isotonic contraction in one dimensional condition is investigated. Firstly, we suppose a relationship between energy and time for a single cross bridge during the working cycle. Then we investigate two particular cooperative behaviors of cross bridges in muscle isotonic contraction(in which the extern load F is constant):(1) n 0 attached cross bridges work at the same tempo, the working process is not affected by the environment;(2) n 0 attached cross bridges work at the same tempo, and the working rate is proportional to the very velocity of thin filament in the contraction. We have calculated the relationship between the extern load to muscle and the velocity of muscle contraction in the two conditions.We find that in the first case it is similar to the Hill curve in shape,and in the second case the velocity is inversely proportional to the force.