Cohen-Armon M
Biophys Chem. 1984 Nov;20(4):285-98. doi: 10.1016/0301-4622(84)80019-8.
The time and voltage dependence of sodium currents in the Myxicola giant axon were examined as functions of the external sodium concentration. The results were incompatible with a model of free diffusion through a gated channel, but lent themselves to analysis in terms of a model involving a positive cooperative homotropic reaction in which Na+ interacts with two allosteric sites - a regulatory site and a transfer site - at the 'sodium channel'. The time-dependent solution of the rate equations describing the kinetics of the transfer reaction was derived as an expression describing the sodium current as a function of time, membrane potential and external sodium concentration. This function was used to test the validity of the model by its ability to predict the nerve excitability properties. The predicted i-v and i-t curves fitted the experimental results (p less than 0.005 and p less than 0.05, respectively). The computed parameters of these functions are consistent with other experimental results. The possibility of a noncooperative reaction was rejected.
研究了黏液虫巨大轴突中钠电流的时间和电压依赖性与外部钠浓度的关系。结果与通过门控通道自由扩散的模型不相符，但适合用一个涉及正协同同促反应的模型进行分析，在该模型中，Na⁺与“钠通道”上的两个变构位点——一个调节位点和一个转运位点相互作用。推导了描述转运反应动力学的速率方程的时间相关解，作为描述钠电流随时间、膜电位和外部钠浓度变化的表达式。该函数通过预测神经兴奋性特性的能力来检验模型的有效性。预测的电流-电压（i-v）和电流-时间（i-t）曲线与实验结果相符（p分别小于0.005和0.05）。这些函数的计算参数与其他实验结果一致。排除了非协同反应的可能性。
