Hu G Y
Institute of Neurophysiology, University of Oslo, Norway.
Acta Physiol Scand. 1991 Feb;141(2):235-40. doi: 10.1111/j.1748-1716.1991.tb09073.x.
A slow prepotential preceding the action potential elicited by 40-80 ms depolarizing current pulses injected in CA1 pyramidal cells in rat hippocampal slices was isolated and characterized using a subtraction procedure. The exponentially rising slow prepotential showed enhanced amplitude at depolarized membrane potential levels. In sufficient doses, intracellular injection of the lidocaine derivative QX-314 selectively blocked the slow prepotential, leaving the action potential largely unchanged. These results suggest that the slow prepotential might be mediated by a persistent sodium conductance or threshold channels recently found in various nerve cells, and could trigger action potentials in situations with a long-lasting depolarization.
通过减法程序分离并表征了在大鼠海马切片的CA1锥体细胞中注入40 - 80毫秒去极化电流脉冲所引发的动作电位之前的缓慢预电位。指数上升的缓慢预电位在去极化膜电位水平时幅度增强。在足够剂量下，细胞内注射利多卡因衍生物QX - 314可选择性阻断缓慢预电位，而动作电位基本不变。这些结果表明，缓慢预电位可能由最近在各种神经细胞中发现的持续性钠电导或阈值通道介导，并且在长期去极化的情况下可能触发动作电位。
