Abstract：
The contraction activation of smooth muscle in the stomach wall (SW) is coordinated by slow electrical waves. The interstitial cells of Cajal (ICC), specialised pacemaker cells, initiate and propagate these slow waves. By establishing an electrically coupled network, each ICC adjusts its intrinsic pacing frequency to a single dominant frequency, to be a key aspect in modelling the electrophysiology of gastric tissue. In terms of modelling, additional fields associated with electrical activation, such as voltage-dependent calcium influx and the resulting deformation, have hardly been considered so far. Here we present a three-dimensional model of the electro-chemomechanical activation of gastric smooth muscle contractions. To reduce computational costs, an adaptive multi-scale discretisation strategy for the temporal resolution of the electric field is used. The model incorporates a biophysically based model of gastric ICC pacemaker activity that aims to simulate stable entrainment and physiological conduction velocities of the electrical slow waves. Together with the simulation of concomitant gastric contractions and the inclusion of a mechanical feedback mechanism, the model is used to study dysrhythmias of gastric slow waves induced by abnormal stretching of the antral SW. The model is able to predict the formation of stretch-induced gastric arrhythmias, such as the emergence of an ectopic pacemaker in the gastric antrum. The results show that the ectopic event is accompanied by smooth muscle contraction and, although it disrupts the normal propagation pattern of gastric slow electrical waves, it can also catalyse the process of handling indigestible materials that might otherwise injure the gastric SW.
摘要：
胃壁（SW）中平滑肌的收缩激活由慢电波协调。Cajal间质细胞（ICC），专门的起搏器细胞,启动和传播这些慢波。通过建立电耦合网络，每个ICC将其固有起搏频率调整为单个主频率，成为胃组织电生理学建模的一个关键方面。在建模方面,与电激活相关的其他字段，例如电压依赖性钙流入和由此产生的变形，到目前为止几乎没有考虑过。在这里，我们提出了胃平滑肌收缩的电化学机械激活的三维模型。为了降低计算成本，使用自适应多尺度离散化策略来计算电场的时间分辨率。该模型结合了基于生物物理的胃ICC起搏器活动模型，旨在模拟慢波的稳定夹带和生理传导速度。同时模拟伴随的胃收缩和包含机械反馈机制，该模型用于研究由胃窦SW异常拉伸引起的胃慢波节律障碍。该模型能够预测拉伸引起的胃心律失常的形成，例如胃窦异位起搏器的出现。结果表明,异位事件伴随着平滑肌收缩,尽管它破坏了胃慢电波的正常传播模式，它还可以催化处理可能损害胃SW的难消化材料的过程。
