PDF(Pubmed)
Abstract：
Heating cardiomyocytes to 38-42°C induces hyperthermal sarcomeric oscillations (HSOs), which combine chaotic instability and homeostatic stability. These properties are likely important for achieving periodic and rapid ventricular expansion during the diastole phase of the heartbeat. Compared with spontaneous oscillatory contractions in cardiomyocytes, which are sarcomeric oscillations induced in the presence of a constant calcium concentration, we found that calcium concentration fluctuations cause chaotic instability during HSOs. We believe that the experimental fact that sarcomeres, autonomously oscillating, exhibit such instability due to the action of calcium concentration changes is important for understanding the physiological function of sarcomeres. Therefore, we have named this chaotic sarcomere instability that appears under conditions involving changes in calcium concentration as Sarcomere Chaos with Changes in Calcium Concentration (S4C). Interestingly, sarcomere instability that could be considered S4C has also been observed in the relaxation dynamics of EC coupling. Unlike ADP-SPOCs and Cell-SPOCs under constant calcium concentration conditions, fluctuations in oscillation amplitude indistinguishable from HSOs were observed. Additionally, like HSO, a positive Lyapunov exponent was measured. S4C is likely a crucial sarcomeric property supporting the rapid and flexible ventricular diastole with each heartbeat of the heart.
摘要：
将心肌细胞加热至38-42°C会诱导高温肌节振荡（HSO），它结合了混沌不稳定性和稳态稳定性。这些特性对于在心跳的舒张期期间实现周期性和快速的心室扩张可能是重要的。与心肌细胞自发振荡收缩相比，它们是在恒定钙浓度存在下诱导的肌节振荡，我们发现钙浓度的波动会导致HSO过程中的混沌不稳定。我们相信肉瘤的实验事实，自主振荡，由于钙浓度变化的作用而表现出这种不稳定性对于理解肉瘤的生理功能很重要。因此,我们将这种在涉及钙浓度变化的条件下出现的混沌肌节不稳定性命名为钙浓度变化的肌节混沌（S4C）。有趣的是,在EC耦合的弛豫动力学中也观察到了可以被认为是S4C的肌节不稳定性。与ADP-SPOCs和细胞-SPOCs在恒定钙浓度条件下不同，观察到振荡振幅的波动与HSO无法区分。此外,像HSO一样,测量了正的Lyapunov指数。S4C可能是至关重要的肌节特性，可支持心脏的每次心跳快速而灵活的心室舒张。
