Service de physiologie, hôpital de Bicêtre, Assistance publique-Hôpitaux de Paris, France.
C R Biol. 2011 Oct;334(10):725-36. doi: 10.1016/j.crvi.2011.08.001. Epub 2011 Sep 13.
Statistical mechanics establishes a link between microscopic properties of matter and its bulk properties. A. Huxley's equations (1957) [1] provide the necessary phenomenological formalism to use statistical mechanics.
We compared statistical mechanics in rat diaphragm in tetanus (tet; n=10) and twitch (tw; n=12) modes, in heart in twitch mode (n=20), and in tracheal smooth muscle in tetanus mode (TSM; n=10). This powerful tool makes it possible to determine: (i) statistical entropy (S) which is related to the dispersal of energy and represents a measure of the degree of disorder in muscular system; (ii) thermodynamic force A/T (chemical affinity A and temperature T); (iii) thermodynamic flow (υ); (iv) entropy production rate (A/T×υ), which quantifies irreversible chemical processes generated by myosin crossbridge (CB) molecular motors.
All muscles studied operated near equilibrium, i.e., A<<2500J/mol and in a stationary linear regime, i.e., A/T varied linearly with υ. The heart operated farther from equilibrium than both diaphragm (tet and tw) and TSM, as attested by its high entropy production rate. S was of the same order of magnitude in heart and TSM but lower in diaphragm (tet and tw).
CB kinetics derived from A. Huxley's equations conferred a characteristic profile in terms of statistical mechanics on each muscle type. All studied muscles differed in terms of statistical entropy, chemical affinity, and entropy production rate. Stimulation mode (tet and tw) modulated CB kinetics and statistical mechanics. All muscle types operated near equilibrium and in a stationary linear regime.
统计力学在物质的微观性质与其宏观性质之间建立了联系。A.赫胥黎的方程（1957 年）[1]提供了使用统计力学的必要唯象形式主义。
我们比较了在强直（tet；n=10）和抽搐（tw；n=12）模式下的大鼠膈肌、抽搐模式下的心脏（n=20）和强直模式下的气管平滑肌（TSM；n=10）中的统计力学。这个强大的工具使我们能够确定：（i）统计熵（S），它与能量的分散有关，代表肌肉系统无序程度的度量；（ii）热力学力 A/T（化学亲和力 A 和温度 T）；（iii）热力学流（υ）；（iv）熵产生率（A/T×υ），它量化了肌球蛋白交联（CB）分子马达产生的不可逆化学过程。
所有研究的肌肉都接近平衡，即 A<<2500J/mol，并且处于稳定的线性状态，即 A/T 随 υ 线性变化。心脏比膈肌（tet 和 tw）和 TSM 更远离平衡，这反映在其较高的熵产生率上。心脏和 TSM 的 S 处于相同数量级，但膈肌（tet 和 tw）的 S 较低。
A.赫胥黎的方程衍生的 CB 动力学赋予了每种肌肉类型在统计力学方面的特征轮廓。所有研究的肌肉在统计熵、化学亲和力和熵产生率方面都有所不同。刺激模式（tet 和 tw）调节 CB 动力学和统计力学。所有肌肉类型都接近平衡并处于稳定的线性状态。
