Voltage-gated sodium channel (Nav1.1-Nav1.9) (Nav1.1-Nav1.9)

Voltage-gated sodium channels (Nav1.1–Nav1.9) are a family of nine transmembrane alpha subunits that form the pore of sodium-selective ion channels essential for the initiation and propagation of action potentials in excitable cells [1, 4, 12]. These channels open in response to membrane depolarization, allowing a rapid influx of sodium ions that triggers the rising phase of the action potential in neurons, cardiomyocytes, and skeletal muscle fibers [12, 16, 19]. Each channel consists of a large pore-forming alpha subunit, which can be associated with one or more auxiliary beta subunits that modulate gating and trafficking [2, 5, 12]. Mutations in the genes encoding these channels (SCN1A through SCN11A) are associated with a variety of channelopathies, including epilepsy, chronic pain syndromes, and cardiac arrhythmias [2, 6, 15]. Pharmacologically, they are the primary targets for local anesthetics, anti-epileptic drugs, and certain anti-arrhythmics, which typically act by blocking the channel pore or stabilizing the inactivated state [1, 7, 19]. Non-selective blockers often have a narrow therapeutic index due to off-target effects, such as cardiac toxicity from Nav1.5 inhibition or CNS side effects from Nav1.1-1.3 inhibition [1, 15, 18]. Modern drug development focuses on isoform-specific inhibitors, particularly for Nav1.7, Nav1.8, and Nav1.9, to treat pain without the systemic side effects associated with non-selective sodium channel blockers [5, 9, 18]. These channels are also the targets of various natural toxins, such as tetrodotoxin and saxitoxin, which have been instrumental in mapping the channel's functional domains [1, 17, 19].

Other names

Sodium channel protein type 1 subunit alphaSodium channel protein type 2 subunit alphaSodium channel protein type 3 subunit alphaSodium channel protein type 4 subunit alphaSodium channel protein type 5 subunit alphaSodium channel protein type 8 subunit alphaSodium channel protein type 9 subunit alphaSodium channel protein type 10 subunit alphaSodium channel protein type 11 subunit alphaSCN1ASCN2ASCN3ASCN4ASCN5ASCN8ASCN9ASCN10ASCN11AVGSCVDSC

Drugs targeting these channels primarily act through pore blockade or by stabilizing the inactivated state of the channel, often in a use-dependent or voltage-dependent manner [1, 6, 7, 12].