Tokimasa T, Shirasaki T, Yoshida M, Ito M, Tanaka E, Mitsumoto T, Akasu T, Tanaka M, Higashi H, Nakano T
Department of Physiology, Tokai University Medical School, Isehara, Japan.
Neurosci Lett. 1996 Aug 23;214(2-3):79-82. doi: 10.1016/0304-3940(96)12890-1.
Whole-cell voltage-clamp recordings were made from cultured bullfrog sympathetic neurons to measure the steady-state activation curve of M-type potassium current. When measured with a calcium-deficient (10 nM) pipette solution M-conductance was 4.8 nS at -35 mV having the 50%-activation voltage at-20 mV. Respective values were 17.2 nS at -35 mV with the 50%-activation voltage at -42 mV when measured with a calcium-rich (1 microM) solution, indicating the hyperpolarizing displacement of the activation curve with high internal calcium. It is suggested that intracellular calcium ions can modulate kinetics of M-current which thereby regulate the number of M-channels being open at given membrane potentials.
采用全细胞电压钳记录技术，对培养的牛蛙交感神经元进行记录，以测量M型钾电流的稳态激活曲线。当用缺钙（10 nM）的电极内液进行测量时，在-35 mV时M电导为4.8 nS，50%激活电压为-20 mV。当用富含钙（1 μM）的溶液进行测量时，在-35 mV时相应的值为17.2 nS，50%激活电压为-42 mV，这表明在高细胞内钙的情况下激活曲线发生超极化位移。提示细胞内钙离子可调节M电流的动力学，从而在给定膜电位下调节开放的M通道数量。
