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A model analysis of the affect of slow ion channels in muscle stiffness

慢离子通道对肌肉僵硬影响的模型分析

基本信息

批准号：
14550061
负责人：
TERADA Kazuko
金额：
$ 2.24万
依托单位：
Toho University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2002
资助国家：
日本
起止时间：
2002 至 2004
项目状态：
已结题

项目摘要

In some cases of myotonia, one of the ion channel diseases, i.e. channelopathies, muscle stiffness lasts rather long, and in some other cases, it ceases quickly. The former cases are well described by the Hodgkin-Huxley equations for muscle fibers (denoted HHM below), as we have shown before. The ever-lasting myotonia corresponds to the periodic solutions in HHM.The purpose of our study is to clarify how the short stiffness, the latter cases occur.Bifurcation phenomena of HHM for mammalian are investigated by the theory of nonlinear dynamical systems and numerical calculations.The bifurcation phenomena of HHM with chloride conductance and some parameters of sodium channel characteristics as bifurcation parameters are analyzed and the affect of the complex eigenvalues of the equilibrium points are examined, first. Former studies on the Hodgkin-Huxley equations for nerve (denoted just HH below) show when the slow sodium channel are added to the original HH, the periodic solutions are replaced by transient activity of three or four firing in some parameter range. Although we constructed the HHM with slow sodium channel next, we can not derive the same phenomena as the nerve. Physiological studies imply the importance of calcium-dependent channels. So we set of calcium-dependent sodium channels in HHM. However, we could not see the short-range firings. Further study in parameter values of HHM will be done.

在某些情况下，肌强直，离子通道疾病之一，即通道病，肌肉僵硬持续相当长的时间，在其他一些情况下，它很快停止。前一种情况可以用肌纤维的霍奇金-赫胥黎方程（下面记为HHM）很好地描述，正如我们之前所展示的。持续的肌强直对应于HHM中的周期解。我们研究的目的是阐明短刚度，本文用非线性动力系统理论和数值计算方法研究了哺乳动物HHM的分岔现象，分析了以氯离子电导和钠通道特性参数为分岔参数的HHM分岔现象，并讨论了氯离子电导和钠通道特性参数对HHM分岔的影响。首先检查平衡点的复特征值。以前对神经的Hodgkin-Huxley方程（以下仅表示为HH）的研究表明，当慢钠通道被添加到原始HH时，周期解被在某些参数范围内的三个或四个放电的瞬时活动所取代。虽然我们接下来构建了含慢钠通道的HHM，但我们不能推导出与神经相同的现象。生理学研究暗示了钙依赖性通道的重要性。因此，我们在HHM中设置了钙依赖性钠通道。然而，我们看不到短程射击。HHM的参数取值有待进一步研究。