School of Physical Science and Technology, Inner Mongolia University, 235 West Daxue Street, Hohhot, Inner Mongolia 010021, China.
School of Physical Science and Technology, Inner Mongolia University, 235 West Daxue Street, Hohhot, Inner Mongolia 010021, China; Department of Resource Engineering, Ordos Vocational College, Yikezhao Street, Kangbashi New District, Ordos, Inner Mongolia 017000, China.
Biophys Chem. 2019 Oct;253:106221. doi: 10.1016/j.bpc.2019.106221. Epub 2019 Jul 8.
The Ca induced Spontaneous Oscillatory Contraction (Ca-SPOC) of cardiac myofibrils oscillate with a period similar to resting heartbeat of several animal species, and its auto-oscillatory properties set the basic rhythm of cardiac contraction. To explain the dynamics of Ca-SPOC, the present paper constructs a novel chemical kinetical model based upon the cooperative behavior between the two heads of myosin II dimer, also considering the reaction-diffusion effect of ATP inside myocardial fibers. The simulation results show that the concentration of ATP inside myocardial fibers oscillates over time under some special conditions, together with the proportions of myosin II dimers in different states periodically changing with time, which contributes to produce the sustained oscillations of contractive tension. These results indicate that the SPOC of muscles may be partly due to chemical oscillation involved in the actomyosin ATPase cycle, which has been ignored by the previous theoretical studies.
心肌纤维的钙诱导自发性振荡收缩（Ca-SPOC）以与几种动物物种的静息心跳相似的周期振荡，其自动振荡特性为心脏收缩设定了基本节律。为了解释 Ca-SPOC 的动力学，本文基于肌球蛋白 II 二聚体的两个头部之间的协同行为构建了一个新的化学动力学模型，同时还考虑了心肌纤维内 ATP 的反应扩散效应。模拟结果表明，在某些特殊条件下，心肌纤维内的 ATP 浓度随时间振荡，同时肌球蛋白 II 二聚体在不同状态下的比例也随时间周期性变化，这有助于产生收缩张力的持续振荡。这些结果表明，肌肉的 SPOC 可能部分是由于肌球蛋白 II 与 ATP 酶循环相关的化学振荡所致，这一点被以前的理论研究所忽略。
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