Moradi N, Scholkmann F, Salari V
Department of Physics, Isfahan University of Technology, Isfahan, Iran.
J Integr Neurosci. 2015 Mar;14(1):1-17. doi: 10.1142/S021963521550003X. Epub 2014 Dec 7.
The Hodgkin-Huxley (HH) model is a powerful model to explain different aspects of spike generation in excitable cells. However, the HH model was proposed in 1952 when the real structure of the ion channel was unknown. It is now common knowledge that in many ion-channel proteins the flow of ions through the pore is governed by a gate, comprising a so-called "selectivity filter" inside the ion channel, which can be controlled by electrical interactions. The selectivity filter (SF) is believed to be responsible for the selection and fast conduction of particular ions across the membrane of an excitable cell. Other (generally larger) parts of the molecule such as the pore-domain gate control the access of ions to the channel protein. In fact, two types of gates are considered here for ion channels: the "external gate", which is the voltage sensitive gate, and the "internal gate" which is the selectivity filter gate (SFG). Some quantum effects are expected in the SFG due to its small dimensions, which may play an important role in the operation of an ion channel. Here, we examine parameters in a generalized model of HH to see whether any parameter affects the spike generation. Our results indicate that the previously suggested semi-quantum-classical equation proposed by Bernroider and Summhammer (BS) agrees strongly with the HH equation under different conditions and may even provide a better explanation in some cases. We conclude that the BS model can refine the classical HH model substantially.
霍奇金-赫胥黎（HH）模型是一个用于解释可兴奋细胞中动作电位产生不同方面的强大模型。然而，HH模型是在1952年提出的，当时离子通道的真实结构尚不清楚。现在大家都知道，在许多离子通道蛋白中，离子通过孔道的流动由一个门控机制控制，该机制包括离子通道内部的一个所谓“选择性过滤器”，它可以通过电相互作用进行控制。选择性过滤器（SF）被认为负责特定离子在可兴奋细胞膜上的选择和快速传导。分子的其他（通常较大）部分，如孔道结构域门控，控制离子进入通道蛋白。实际上，这里考虑离子通道有两种类型的门：“外部门”，即电压敏感门，以及“内部门”，即选择性过滤器门（SFG）。由于SFG尺寸较小，预计会有一些量子效应，这可能在离子通道的运作中发挥重要作用。在这里，我们研究HH广义模型中的参数，以查看是否有任何参数会影响动作电位的产生。我们的结果表明，先前由伯恩罗伊德和萨姆哈默（BS）提出的半量子-经典方程在不同条件下与HH方程高度一致，甚至在某些情况下可能提供更好的解释。我们得出结论，BS模型可以显著改进经典的HH模型。
