Voltage-gated sodium channel (fast inactivation mechanism) (NaV channel)

Voltage-gated sodium channels are integral membrane proteins that selectively conduct sodium ions (Na⁺) through the plasma membrane in response to changes in membrane potential, enabling the generation and propagation of action potentials in neuronal, muscular, and other excitable cells. The channel consists of a large alpha subunit, which forms the pore and functional core, and may associate with smaller accessory beta subunits. Fast sodium channels refer specifically to the rapid activation and inactivation mechanisms shaped by the classic “hinged-lid” inactivation gate (DIII-IV linker), which closes the channel pore within milliseconds after opening, thus terminating sodium influx. This fast inactivation is fundamentally required to reset membrane excitability and regulate repetitive firing. Drugs that target fast sodium channels predominantly bind inside the channel pore, most often in a state-dependent manner, either stabilizing the fast- or slow-inactivated conformations. Clinically, blockade or modulation of these channels is central for local anesthesia, antiarrhythmic therapy, anticonvulsant action, and newer pain treatments. Mutations or perturbations in sodium channel function are linked to a range of diseases and therapeutic outcomes, but off-target effects and non-selectivity among subtypes remain a therapeutic challenge.

Other names

Sodium channelFast sodium channelVoltage-gated sodium channelNaV channelSodium channel protein

Blockade of sodium conductance (inhibition of sodium current). Stabilization of fast-inactivated channel state. Stabilization of slow-inactivated state (less common). Modulate channel inactivation kinetics. State-dependent binding within the channel pore.