Department of Molecular Sciences, Macquarie University, Sydney, NSW, Australia.
Department of Physics, University of Guelph, Guelph, ON, Canada.
Eur Biophys J. 2021 Sep;50(6):819-828. doi: 10.1007/s00249-021-01547-z. Epub 2021 Jun 28.
The simple Goldman-Hodgkin-Katz model for resting-state membrane potentials has been generalized to provide a new nonlinear theoretical model for action potentials in perfused axons. Our minimalistic model appeals naturally to physically based electrodiffusion principles to describe electric-current densities inside sodium and potassium-ion channels whereas the 1952 Hodgkin-Huxley model describes such current densities in an ad hoc way. Although the two models share similar schemes for the kinetics of ion-channel gating, our relaxation times for channel gating are simpler, being independent of membrane potential. Like the theoretical model of Hodgkin and Huxley, based primarily on experimental data at [Formula: see text], our dynamical system behaves as a 4-dimensional resonator exhibiting subthreshold oscillations. Although our present analysis refers to experiments at [Formula: see text], re-parameterizations of this model should permit consideration of action potentials at alternative temperatures. The predicted speed of propagating action potentials in giant axons of squid at [Formula: see text] is in excellent agreement with the Hodgkin-Huxley experimental value at [Formula: see text]. In cases where our model predictions differ from those of the Hodgkin-Huxley model, new experiments will be required to determine which model is more accurate.
已经将简单的 Goldman-Hodgkin-Katz 静息膜电位模型推广为一种新的用于灌流轴突动作电位的非线性理论模型。我们的极简模型自然地诉诸基于物理的电扩散原理来描述钠离子和钾离子通道内的电流密度,而 1952 年的 Hodgkin-Huxley 模型则以特定的方式描述这种电流密度。尽管这两个模型在离子通道门控的动力学方面具有相似的方案,但我们的通道门控弛豫时间更为简单,与膜电位无关。与主要基于 [Formula: see text] 实验数据的 Hodgkin 和 Huxley 理论模型一样,我们的动力系统表现为具有亚阈值振荡的 4 维谐振器。尽管我们目前的分析涉及到 [Formula: see text] 的实验,但对该模型的重新参数化应该允许考虑替代温度下的动作电位。在 [Formula: see text] 下鱿鱼巨大轴突中传播动作电位的预测速度与 [Formula: see text] 下 Hodgkin-Huxley 的实验值非常吻合。在我们的模型预测与 Hodgkin-Huxley 模型的预测不同的情况下,需要进行新的实验来确定哪个模型更准确。