Sodium voltage-gated channel alpha subunit (Nav alpha subunit) (Nav alpha subunit)

Sodium voltage-gated channel alpha subunits are the primary pore-forming components of voltage-gated sodium channels (Nav), essential for the initiation and propagation of action potentials in excitable cells such as neurons, cardiomyocytes, and skeletal muscle fibers [1, 7]. In humans, there are nine functional alpha subunits (Nav1.1–Nav1.9), each encoded by a distinct SCN gene and exhibiting specific tissue distribution and biophysical properties [3, 8]. These large transmembrane proteins consist of four homologous domains that form a sodium-selective pore and contain voltage-sensing modules that respond to membrane depolarization [2, 10]. Mutations in these subunits are linked to a wide range of 'channelopathies,' including epilepsy, chronic pain syndromes, and cardiac arrhythmias [4, 9]. Pharmacologically, they are the targets of diverse classes of drugs, including local anesthetics, antiarrhythmics, and anticonvulsants, which typically act by blocking the pore or modulating channel gating in a state-dependent manner [6, 11]. Recent drug discovery efforts focus on developing subtype-selective inhibitors, such as Nav1.8-selective suzetrigine, to improve therapeutic efficacy and reduce side effects associated with non-selective blockade [1, 3].

Other names

Voltage-gated sodium channel alpha subunitVGSC alpha subunitNav alpha subunitSodium channel protein subunit alphaSCNNav

Drugs targeting these subunits primarily act through pore blockade or gating modulation [1, 6]. Many clinical agents exhibit state-dependent inhibition, meaning they have a higher affinity for the open or inactivated states of the channel, which allows them to selectively suppress high-frequency pathological firing (as seen in seizures or arrhythmias) while sparing normal low-frequency signaling [2, 11, 14].