Recent work has established that axons have a periodic skeleton structure comprising of azimuthal actin rings connected via longitudinal spectrin tetramer filaments. This structure endows the axon with structural integrity and mechanical stability. Additionally, voltage-gated sodium channels follow the periodicity of the active-spectrin arrangement, spaced ~190 nm segments apart. The impact of this periodic sodium channel arrangement on the generation and propagation of action potentials is unknown. To address this question, we simulated an action potential using the Hodgkin-Huxley formalism in a cylindrical compartment but instead of using a homogeneous distribution of voltage-gated sodium channels in the membrane, we applied the experimentally determined periodic arrangement. We found that the periodic distribution of voltage-gated sodium channels does not significantly affect the generation or propagation of action potentials, but instead leads to high-density sodium channel nanodomains. This work provides a foundation for future studies investigating the role of the voltage-gated sodium channel periodic arrangement in the axon.

中文翻译：

---

周期性轴突膜骨架导致高密度钠纳米域，但不影响动作电位

最近的工作已经确定，轴突具有周期性的骨架结构，该结构包括通过纵向光谱素四聚体丝连接的方位角肌动蛋白环。这种结构使轴突具有结构完整性和机械稳定性。此外，电压门控钠通道遵循活性谱排列的周期性，间隔约190 nm。这种周期性的钠通道排列对动作电位的产生和传播的影响尚不清楚。为了解决这个问题，我们在圆柱隔室中使用霍奇金-赫克斯利形式主义模拟了一个动作电位，但不是使用膜中电压门控钠通道的均匀分布，而是应用了实验确定的周期性排列。我们发现电压门控钠通道的周期性分布不会显着影响动作电位的产生或传播，而是会导致高密度钠通道纳米域。这项工作为今后研究电压门控钠通道周期性排列在轴突中的作用提供了基础。