Van Lamsweerde-Gallez D, Meessen A
J Membr Biol. 1978 Apr 20;40(1):39-66. doi: 10.1007/BF01909738.
The model, used previously to account for the transport of K+ ions through squid axon membranes under steady-state conditions, is extended to the description of the kinetic behavior of Na+ and K+ currents, for sudden variations of the applied potential. Theoretical curves are obtained by numerical integration of the electrodiffusion equation for ions within pores, with variable boundary conditions resulting from a progressive reorientation of dipoles at the pore surface. The pores are supposed to be selective and the dipole parameters are allowed to be different for Na+ and K+ pores. The K+ current varies with time, in agreement with the K+ dipole parameters deduced from the steady-state results of Gilbert and Ehrenstein (1969). The dipole parameters for Na+ current are deduced from the steady-state results of Armstrong, Bezanilla & Rojas (1973), where the inactivation phase of the Na+ current is suppressed by introducing pronase in the inside solution. The dipole reorientation is relavent to explain the sigmoid shape of the activation phase of the Na+ current, while the inactivation phase seems to resort to another physical mechanism. The predictions based on this model agree with the experimental results for the steady-state negative resistance and the gating current, associated both with a reorientation of surface dipoles, as well as the activation phase of the Na+ current using a consistent set of parameters for all these comparisons.
该模型先前用于解释稳态条件下钾离子通过鱿鱼轴突膜的运输，现扩展用于描述钠离子和钾离子电流在施加电位突然变化时的动力学行为。通过对孔内离子的电扩散方程进行数值积分，并考虑孔表面偶极子逐渐重新定向所产生的可变边界条件，得到了理论曲线。假设孔具有选择性，并且钠离子孔和钾离子孔的偶极参数不同。钾离子电流随时间变化，这与从吉尔伯特和埃伦斯坦（1969年）的稳态结果推导得出的钾离子偶极参数一致。钠离子电流的偶极参数是根据阿姆斯特朗、贝萨尼利亚和罗哈斯（1973年）的稳态结果推导得出的，在该实验中，通过在内部溶液中加入链霉蛋白酶来抑制钠离子电流的失活阶段。偶极子重新定向有助于解释钠离子电流激活阶段的S形曲线，而失活阶段似乎涉及另一种物理机制。基于该模型的预测与稳态负电阻和门控电流的实验结果一致，这两者都与表面偶极子的重新定向以及使用一组一致参数的钠离子电流激活阶段相关，适用于所有这些比较。
