Tokimasa T, Akasu T
Kurume Med J. 1989;36(2):49-57. doi: 10.2739/kurumemedj.36.49.
Cultured bullfrog dorsal root ganglion cells were voltage-clamped in the whole-cell configuration. The classical delayed rectifier potassium current (IK) was separated from other ionic currents. Tetraethylammonium (1-50 mM) depressed the amplitude of IK in a concentration-dependent manner, a complete block occurring with 30 mM. With the concentration of potassium ions in the superfusate at 20 mM, the reversal potential of IK amounted to about -30mV. IK was activated between -30 and +70 mV. The half activation of IK occurred at +15 mV. The amplitude of IK was increased e-fold with 13.6 mV depolarization. The time constant of IK de-activation was shortened with membrane hyperpolarization (tau congruent to 4 ms at -100 mV). Finally, reciprocal time constant (tau -1) of the de-activating IK was increased e-fold with congruent to 13 mV hyperpolarization. It appears that the properties of IK in amphibian afferent neurons are comparable to those which have been observed with respect to the IK of the squid giant axons (Hodgkin and Huxley, 1952).
将培养的牛蛙背根神经节细胞以全细胞模式进行电压钳制。经典的延迟整流钾电流（IK）与其他离子电流分离。四乙铵（1 - 50 mM）以浓度依赖的方式降低IK的幅度，30 mM时出现完全阻断。当灌流液中钾离子浓度为20 mM时，IK的反转电位约为 - 30 mV。IK在 - 30至 + 70 mV之间被激活。IK的半激活发生在 + 15 mV。IK的幅度在去极化13.6 mV时增加e倍。IK失活的时间常数随膜超极化而缩短（在 - 100 mV时τ约为4 ms）。最后，失活的IK的倒数时间常数（τ-1）在超极化约13 mV时增加e倍。两栖类传入神经元中IK的特性似乎与鱿鱼巨轴突的IK所观察到的特性相当（霍奇金和赫胥黎，1952）。
