Huang L Y, Moran N, Ehrenstein G
Proc Natl Acad Sci U S A. 1982 Mar;79(6):2082-5. doi: 10.1073/pnas.79.6.2082.
We have studied the effects of batrachotoxin (BTX) on sodium channels in hybrid mouse neuroblastoma cells NG108-15 by using the suction pipet voltage clamp method. BTX-modified sodium channels activate with first-order kinetics and, over most of the potential range, activate more slowly than normal sodium channels. The peak conductance-voltage curve and the time constant of activation-versus-voltage curve for BTX-modified sodium channels are shifted about 50 mV in the hyperpolarizing direction compared to the corresponding curves for normal sodium channels. There is no change in the slope of the conductance-voltage curve. These results suggest that BTX slows down one of the steps leading to channel opening, which consequently becomes rate-limiting. In addition, BTX eliminates both fast and slow inactivation.
我们运用吸液管电压钳法研究了蛙毒素（BTX）对杂交小鼠神经母细胞瘤细胞NG108-15中钠通道的影响。BTX修饰的钠通道以一级动力学激活，并且在大部分电位范围内，其激活速度比正常钠通道慢。与正常钠通道的相应曲线相比，BTX修饰的钠通道的峰值电导-电压曲线和激活时间常数-电压曲线在超极化方向上偏移了约50 mV。电导-电压曲线的斜率没有变化。这些结果表明，BTX减缓了导致通道开放的步骤之一，因此该步骤成为限速步骤。此外，BTX消除了快速和慢速失活。
