Ogawa Yasuhiro, Rasband Matthew N
Department of Neuroscience, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA.
Curr Opin Neurobiol. 2008 Jun;18(3):307-13. doi: 10.1016/j.conb.2008.08.008.
Action potential initiation, modulation, and duration in neurons depend on a variety of Na+ and K+ channels that are highly enriched at the axon initial segment (AIS). The AIS also has high densities of cell adhesion molecules (CAMs), modulatory proteins, and a unique extracellular matrix (ECM). In contrast to other functional domains of axons (e.g. the nodes of Ranvier and axon terminals) whose development depends on the interactions with different cells (e.g. myelinating glia and postsynaptic cells), the recruitment and retention of AIS proteins is intrinsically specified through axonal cytoskeletal and scaffolding proteins. We speculate that the AIS has previously unappreciated forms of plasticity that influence neuronal excitability, and that AIS plasticity is regulated by the developmental or activity-dependent modulation of scaffolding protein levels rather than directly altering ion channel expression.
神经元动作电位的起始、调节和持续时间取决于多种在轴突起始段（AIS）高度富集的钠通道和钾通道。AIS还具有高密度的细胞粘附分子（CAMs）、调节蛋白和独特的细胞外基质（ECM）。与轴突的其他功能域（如郎飞结和轴突终末）不同，后者的发育依赖于与不同细胞（如髓鞘形成胶质细胞和突触后细胞）的相互作用，AIS蛋白的募集和保留是通过轴突细胞骨架和支架蛋白内在指定的。我们推测，AIS具有以前未被认识到的影响神经元兴奋性的可塑性形式，并且AIS可塑性是由支架蛋白水平的发育或活动依赖性调节来调控的，而不是直接改变离子通道的表达。
