Voltage-gated sodium channel alpha subunit (NaV) (NaV)

The voltage-gated sodium channel (VGSC) alpha subunit is a critical transmembrane protein that mediates the rapid influx of sodium ions required for the initiation and propagation of action potentials in excitable tissues like the brain, heart, and skeletal muscle (Catterall, 2012 [1]). It is composed of four homologous domains, each containing six transmembrane segments, where the S5 and S6 segments from each domain converge to form the central ion-conducting pore (Payandeh et al., 2011 [2]). This inner pore region is the primary receptor site for many clinically essential drugs, including local anesthetics, antiarrhythmics, and anticonvulsants, which bind to highly conserved residues to block ion flow and stabilize the non-conducting inactivated state (de Lera Ruiz & Kraus, 2015 [3]). Mutations in the various isoforms of the alpha subunit (e.g., NaV1.1, NaV1.5) are associated with diverse channelopathies, including Dravet syndrome, Brugada syndrome, and chronic pain (StatPearls, 2023 [4]). Therapeutic intervention at the inner pore often utilizes use-dependent inhibition, meaning the drug's affinity increases with higher channel activity, which helps target pathological firing while sparing normal physiological function (UniProt, 2024 [5]). This site remains a primary focus for drug discovery aimed at achieving subtype selectivity to minimize systemic side effects such as cardiotoxicity or neurotoxicity.

Other names

Voltage-gated sodium channelNaV channelSodium channel alpha subunitLocal anesthetic binding siteInner pore of sodium channel

Drugs bind to the inner pore of the alpha subunit, physically obstructing the ion conduction pathway and stabilizing the channel in its inactivated state, often in a use-dependent manner (de Lera Ruiz & Kraus, 2015 [3]).