Voltage-dependent conductances not only drive action potentials but also help regulate neuronal resting potential. We found differential regulation of resting potential in the proximal axon of layer 5 pyramidal neurons compared to the soma. Axonal resting potential was more negative than the soma, reflecting differential control by multiple voltage-dependent channels, including sodium channels, Cav3 channels, Kv7 channels, and HCN channels. Kv7 current is highly localized to the axon and HCN current to the soma and dendrite. Because of impedance asymmetry between the soma and axon, axonal Kv7 current has little effect on somatic resting potential, while somatodendritic HCN current strongly influences the proximal axon. In fact, depolarizing somatodendritic HCN current is critical for resting activation of all the other voltage-dependent conductances, including Kv7 in the axon. These experiments reveal complex interactions among voltage-dependent conductances to control region-specific resting potential, with somatodendritic HCN channels playing a critical enabling role.

中文翻译：

---

皮质第 5 层锥体神经元中电压依赖性电导对轴突和体细胞静息电位的差异控制

电压依赖性电导不仅驱动动作电位，还有助于调节神经元静息电位。我们发现，与胞体相比，第 5 层锥体神经元近端轴突的静息电位调节存在差异。轴突静息电位比体细胞更负，反映了多个电压依赖性通道的差异控制，包括钠通道、Cav3 通道、Kv7 通道和 HCN 通道。Kv7 电流高度集中于轴突，HCN 电流高度集中于体细胞和树突。由于体细胞和轴突之间的阻抗不对称，轴突Kv7电流对体细胞静息电位影响很小，而体细胞树突HCN电流对近端轴突影响很大。事实上，去极化体细胞树突 HCN 电流对于所有其他电压依赖性电导（包括轴突中的 Kv7）的静息激活至关重要。这些实验揭示了电压依赖性电导之间复杂的相互作用，以控制区域特异性静息电位，其中体细胞树突 HCN 通道发挥着关键的促进作用。