Voltage-gated sodium channel (NaV) (NaV)

The voltage-gated sodium channel (NaV) is an integral membrane protein complex essential for the initiation and propagation of action potentials in excitable cells, such as neurons and muscle cells [1, 7]. It consists of a large pore-forming alpha subunit and associated beta subunits that modulate channel kinetics and cellular localization [3]. Upon membrane depolarization, the channel opens to allow a rapid influx of sodium ions, a process fundamental to nerve signaling and muscle contraction [6, 13]. Saxitoxin is a potent, naturally occurring alkaloid neurotoxin that binds with high affinity to Receptor Site 1 in the extracellular pore of the sodium channel, physically occluding the path and preventing ion flow [1, 2, 13]. This interaction is the molecular basis for paralytic shellfish poisoning, a condition characterized by progressive muscle paralysis and potentially fatal respiratory failure [7, 10]. While primarily known as a toxicant, saxitoxin and its derivatives like neosaxitoxin are being investigated as long-acting local anesthetics and analgesics for clinical applications such as chronic pain management and surgical anesthesia [5, 8, 12]. Other sodium channel blockers are already established as standard treatments for epilepsy, neuropathic pain, and cardiac arrhythmias [11, 12].

Other names

Sodium channel proteinVoltage-dependent sodium channelSaxitoxin receptorTetrodotoxin-sensitive sodium channelSite 1 sodium channel

Selective blockade of the extracellular pore (Site 1) of the alpha subunit, physically occluding the ion conduction path to prevent sodium influx and inhibit action potential propagation.