Voltage-gated sodium channel (central nervous system subtype) (VGSC (Nav channel); no single abbreviation for CNS-wide channel, but subtypes are denoted as Nav1.1, Nav1.2, etc.)

Voltage-gated sodium channels in the central nervous system are transmembrane proteins responsible for the initiation and propagation of action potentials in neurons, playing a critical role in electrical signaling[1][2][3]. They are large complexes composed of a core α (alpha) subunit—which forms the ion-conducting pore and determines isoform specificity—together with auxiliary β subunits that affect channel kinetics and localization[1][2]. The α subunit contains four homologous domains (I–IV), each with six transmembrane segments (S1–S6)[1][2][3]. The S4 segment acts as the voltage sensor; S5 and S6 (and the connecting loop) define the pore[1][2][3]. Activation by membrane depolarization opens the channel, allowing an influx of Na⁺ ions, which depolarizes the neuron and mediates the upstroke of the action potential[1][2][3][4]. In CNS neurons, several Nav channel subtypes (including Nav1.1/SCN1A, Nav1.2/SCN2A, Nav1.3/SCN3A, and Nav1.6/SCN8A) are expressed, each with distinct physiological and pathophysiological roles[1][2][4]. Central nervous system sodium channels are key targets for multiple antiepileptic drugs and local anesthetics, which inhibit channel function by stabilizing inactive states and reducing abnormal firing[2][3]. Genetic mutations in CNS channel subtypes are linked to a range of neurological channelopathies, including epilepsy, ataxia, and neurodevelopmental disorders[4].

Other names

Voltage-dependent sodium channelVGSCNav channelNa⁺ channel

Blockade of sodium ion conductance through the channel pore; Stabilization of the inactivated state (use-dependent block); Alteration of channel gating kinetics; Inhibition of repetitive neuronal firing