Angaut-Petit D, Mallart A
Neuroscience. 1985 Dec;16(4):1047-56. doi: 10.1016/0306-4522(85)90115-0.
An in vitro study of electrical activity of regenerating motor endings was performed 11-15 days after the crushing of one motor nerve supplying the triangularis sterni muscle in the adult mouse. For this purpose, presynaptic membrane currents elicited by electrical stimulation of the regenerating nerve were recorded by external electrodes. Ionic channel distribution along the length of the endings was deduced from wave form configuration in normal perfusing fluid together with changes produced by application of specific channel blocking agents. The sharp negative deflection which was shown to correspond to inward Na+ current by its sensitivity to tetrodotoxin application could be recorded along most of the length of the endings indicating a widespread distribution of Na channels. Frequent absence of the late wave form component which signals K+ current was taken to indicate an even K+ current density in the few last nodes, the heminode and the distal part of the endings. Therefore, it appears that regenerating motor endings are characterized by an overlap of Na and K conductances all along their length. In the course of regeneration, the heminode loses the sensitivity to K channel blocking agents and the remainder of the terminal becomes insensitive to tetrodotoxin, the former change occurring usually earlier than the latter.
在成年小鼠供应胸骨三角肌的一条运动神经被挤压11 - 15天后，进行了再生运动终末电活动的体外研究。为此，通过外部电极记录电刺激再生神经所引发的突触前膜电流。根据正常灌注液中的波形构型以及应用特定通道阻滞剂所产生的变化，推断离子通道沿终末长度的分布。通过其对河豚毒素应用的敏感性显示与内向Na⁺电流相对应的尖锐负向偏转，可在终末的大部分长度上记录到，这表明Na通道广泛分布。频繁缺失指示K⁺电流的晚期波形成分，被认为表明在最后几个节段、半节段和终末远端部分K⁺电流密度均匀。因此，似乎再生运动终末的特征是在其整个长度上Na和K电导重叠。在再生过程中，半节段失去对K通道阻滞剂的敏感性，终末其余部分对河豚毒素变得不敏感，前一种变化通常比后一种变化发生得更早。
