Koppenhöfer E, Bohuslavizki K H
Institute of Physiology, University of Kiel, FRG.
Gen Physiol Biophys. 1988 Dec;7(6):557-67.
We tried to reproduce some basic implications of the Hodgkin-Huxley-Frankenhaeuser formalism by measuring sodium currents in single myelinated nerve fibres with a commercially available version of the potential clamp device according to Nonner. The following contradictory observations were made: 1. The potential dependence of the time to peak sodium currents showed a discontinuity around the sodium equilibrium potential. 2. Defining the sodium permeability PNa by the constant field equation and fitting the peak PNa-voltage relation by a sigmoid function we obtained unbelievable high values of PNa at rest. 3. Testing PNa as calculated by the constant field equation by so-called "sodium tail current" experiments we obtained instantaneous changes of PNa. Summing up, neither the kinetics of sodium currents nor the constant field concept as tested with the equipment used seem to agree satisfactorily with the standard data of sodium currents in Ranvier nodes.
我们试图通过使用根据诺纳（Nonner）提供的商业版电压钳设备测量单根有髓神经纤维中的钠电流，来重现霍奇金 - 赫胥黎 - 弗兰肯海泽（Hodgkin-Huxley-Frankenhaeuser）形式体系的一些基本含义。我们得到了以下相互矛盾的观察结果：1. 钠电流峰值时间的电位依赖性在钠平衡电位附近表现出不连续性。2. 通过恒定场方程定义钠通透性PNa，并通过S形函数拟合峰值PNa-电压关系，我们在静息状态下得到了高得令人难以置信的PNa值。3. 通过所谓的“钠尾电流”实验测试由恒定场方程计算出的PNa，我们得到了PNa的瞬时变化。总之，无论是钠电流的动力学，还是使用该设备测试的恒定场概念，似乎都与郎飞结中钠电流的标准数据不太相符。
