Gestrelius S, Grampp W, Sjölin L
Acta Physiol Scand. 1983 Jun;118(2):135-40. doi: 10.1111/j.1748-1716.1983.tb07253.x.
The kinetics of the TTX sensitive Na+ current (INa) in the slowly adapting lobster stretch receptor neurone were investigated in sub- and near-threshold voltage regions using electrophysiological and pharmacological techniques. In dynamic conditions INa was found to display both fast and slow reactions. These were attributed to a fast Hodgkin-Huxley type of Na activation and inactivation, and a slow type of Na inactivation, respectively. In stationary conditions the voltage dependence of the slow Na inactivation was shifted in a depolarizing direction by increasing, and in a hyperpolarizing direction by decreasing the extracellular Ca++ concentration. From this finding as well as from its kinetic properties the slow Na inactivation was classified as a genuine gating process. The processes of fast Na activation and inactivation were too fast for a dynamic analysis with the recording technique available. An estimate of their stationary voltage dependence could however be obtained in a voltage range from about -80 to about -50 mV. The experimental findings were used for the formulation of a mathematical description of INa in the present preparation based on constant field and state transition theories.
运用电生理和药理学技术，在低于阈值和接近阈值的电压区域，研究了缓慢适应的龙虾牵张感受器神经元中TTX敏感的Na⁺电流（INa）的动力学。在动态条件下，发现INa表现出快速和慢速反应。它们分别归因于快速的霍奇金-赫胥黎类型的Na激活和失活，以及慢速的Na失活类型。在静态条件下，通过增加细胞外Ca²⁺浓度，慢速Na失活的电压依赖性向去极化方向移动；通过降低细胞外Ca²⁺浓度，则向超极化方向移动。基于这一发现及其动力学特性，慢速Na失活被归类为一个真正的门控过程。快速Na激活和失活过程太快，无法用现有的记录技术进行动态分析。然而，在约-80至约-50 mV的电压范围内，可以获得它们静态电压依赖性的估计值。基于恒定场和状态转换理论，利用实验结果对本制剂中的INa进行了数学描述。
