Shirokov R E
Neirofiziologiia. 1988;20(2):185-93.
Potential dependence of calcium inward current deactivation kinetics was studied in the somatic membrane of mouse dorsal root ganglion neurons by intracellular dialysis technique. The decay of the high-threshold calcium current upon repolarization was reasonably described by single-exponential process with the time constant tau less than or equal to 130 microseconds (V = = -80 mV), when the intracellular solution contained tris-PO4, and by two-exponential process (tau congruent to 0.1 and tau = 0.8 divided by ms, V = -80 mV), when the intracellular solution contained Cs-aspartate and EGTA. Both time constants were strongly voltage dependent. The amplitude of the fast component of the tail current had sigmoidal voltage dependence, and the slow component had V-shaped voltage dependence. The low-threshold calcium current deactivation occurs more slowly with high voltage dependent kinetics (tau = 1.1 divided by 1.2 ms, V = -160 mV). A dependence of low-threshold current deactivation time constant on the type of penetrating cation was observed. A kinetic model of calcium current deactivation was proposed considering three types of calcium channels presented in the somatic membrane of the neurons studied.
通过细胞内透析技术研究了小鼠背根神经节神经元胞体膜中钙内向电流失活动力学的潜在依赖性。当细胞内溶液含有磷酸三（羟甲基）氨基甲烷（tris-PO4）时，复极化时高阈值钙电流的衰减可用单指数过程合理描述，时间常数τ小于或等于130微秒（V = -80 mV）；当细胞内溶液含有天冬氨酸铯（Cs-天冬氨酸）和乙二醇双四乙酸（EGTA）时，则用双指数过程（τ约为0.1和τ = 0.8毫秒，V = -80 mV）描述。两个时间常数均强烈依赖电压。尾电流快速成分的幅度具有S形电压依赖性，而慢速成分具有V形电压依赖性。低阈值钙电流失活在高电压依赖性动力学情况下发生得更慢（τ = 1.1/1.2毫秒，V = -160 mV）。观察到低阈值电流失活时间常数对穿透性阳离子类型的依赖性。考虑到所研究神经元胞体膜中存在的三种类型的钙通道，提出了钙电流失活的动力学模型。
