The influence of transverse tubular delays on the kinetics of charge movement in mammalian skeletal muscle.
The influence of transverse tubular delays on the kinetics of charge movement in mammalian skeletal muscle.
复制标题
横向管状延迟对哺乳动物骨骼肌电荷运动动力学的影响。
DOI：
10.1085/jgp.85.1.21
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发表时间：
1985-01
期刊：
影响因子：
--
通讯作者：
Beam KG
中科院分区：
文献类型：
--
作者：
Simon BJ;Beam KG
建立了一个模型来描述大鼠肩胛舌骨肌中缓慢的、电压依赖的电荷运动动力学。为了表示横向管状系统（t-系统）的电分布性质，我们采用了类似于Adrian和Peachey（1973年J. Physiol）所描述的方法。[Lond。]。235:103)，并用12个同心的圆柱形外壳来近似纤维。每个外壳都包含电容和导电元件，代表t系统的无源电性能，以及一个代表移动电荷的元件。假设电荷服从两态格式，其中电荷的再分配受一阶反应控制，根据常场表达式，假设连接两态的速率常数依赖于势。这种“分布式双态模型”的预测与在单个纤维中实验测量的电荷运动进行了比较。为了进行比较，首先对模型的无源电参数进行了调整，以拟合实验线性暂态容量。接下来，将玻尔兹曼表达式拟合到光纤的稳态Q vs. V数据中，从而限制了速率常数对电压的依赖，但没有限制它们的绝对值。绝对大小是通过将理论拟合到单个测试电位的实验电荷运动来确定的，这反过来又约束了所有其他测试电位的拟合。分布式双态模型很好地描述了温度范围为3至25摄氏度的ON、OFF和阶梯OFF电荷运动的上升和下降阶段。因此，我们得出结论，管状延迟足以解释实验电荷运动的圆形上升阶段，并且没有必要为潜在的电荷再分配假设高阶反应方案。
A model was developed to describe the kinetics of slow, voltage- dependent charge movement in the rat omohyoid muscle. To represent the electrically distributed nature of the transverse tubular system (t- system), we followed an approach similar to that described by Adrian and Peachey (1973 J. Physiol. [Lond.]. 235:103), and approximated the fiber with 12 concentric cylindrical shells. Incorporated into each shell were capacitative and conductive elements that represented the passive electrical properties of the t-system, and an element representing the mobile charge. The charge was assumed to obey a two- state scheme, in which the redistribution of charge is governed by a first-order reaction, and the rate constants linking the two states were assumed to depend on potential according to the constant field expression. The predictions of this "distributed two-state model" were compared with charge movements experimentally measured in individual fibers. For this comparison, first, the passive electrical parameters of the model were adjusted to fit the experimental linear capacity transient. Next, the Boltzmann expression was fitted to the steady state Q vs. V data of the fiber, thereby constraining the voltage dependence of the rate constants, but not their absolute magnitude. The absolute magnitude was determined by fitting the theory to an experimental charge movement at a single test potential, which in turn constrained the fits at all other test potentials. The distributed two- state model well described the rising and falling phases of ON, OFF, and stepped OFF charge movements at temperatures ranging from 3 to 25 degrees C. We thus conclude that tubular delays are sufficient to account for the rounded rising phase of experimental charge movements, and that it is unnecessary to postulate higher-order reaction schemes for the underlying charge redistribution.
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影响因子：
64.8
作者：
SIGWORTH, FJ;NEHER, E
通讯作者：
NEHER, E
影响因子：
5.5
作者：
HOLLINGWORTH, S;MARSHALL, MW
通讯作者：
MARSHALL, MW
影响因子：
5.5
作者：
ADRIAN, RH;ALMERS, W
通讯作者：
ALMERS, W
影响因子：
64.8
作者：
SCHNEIDER, MF;CHANDLER, WK
通讯作者：
CHANDLER, WK
DOI：
10.1007/bf00299254
发表时间：
1980-01-01
期刊：
ANATOMY AND EMBRYOLOGY
影响因子：
--
作者：
MUNTENER, M;GOTTSCHALL, J;ZENKER, W
通讯作者：
ZENKER, W