Van der Kloot W, Cohen I S
Biophys J. 1984 May;45(5):905-11. doi: 10.1016/S0006-3495(84)84237-X.
At the neuromuscular junction, the end-plate potential is generated by a conductance increase in the end-plate membrane. The end-plate depolarization brings the membrane potential toward the reversal potential, which diminishes the driving force for inward current flow. A. R. Martin (1955, J. Physiol. [Lond.]. 130:114-122) devised a simple formula to correct end-plate potential amplitudes for a diminished driving force based on a purely resistive model of the end-plate membrane. The model ignores the membrane capacity, the complexity of the equivalent circuit for a muscle fiber, the variation in channel lifetimes with changes in membrane potential, and the extension of the end plate along a length of the cable. We have developed a model that incorporates all of these features. The calculations show that Martin's correction is, in theory, quite satisfactory for a cable that has the characteristics of a muscle fiber unless the recording is made at a distance from the site of inward current flow. However, there is a discrepancy between models of the frog neuromuscular junction and the available experimental data, which suggests that the end-plate depolarization produced by a given current is greater than expected from their model.
在神经肌肉接头处，终板电位是由终板膜电导增加产生的。终板去极化使膜电位趋向反转电位，这减小了内向电流流动的驱动力。A. R. 马丁（1955年，《生理学杂志》[伦敦]。130:114 - 122）基于终板膜的纯电阻模型设计了一个简单公式，用于校正因驱动力减小而产生的终板电位幅度。该模型忽略了膜电容、肌肉纤维等效电路的复杂性、通道寿命随膜电位变化的情况以及终板沿电缆长度的延伸。我们开发了一个包含所有这些特征的模型。计算表明，理论上，对于具有肌肉纤维特征的电缆，马丁的校正相当令人满意，除非记录是在距内向电流流动部位有一定距离处进行。然而，青蛙神经肌肉接头模型与现有实验数据之间存在差异，这表明给定电流产生的终板去极化大于其模型的预期。
