Sodium channel protein type 1 subunit alpha, Sodium channel protein type 2 subunit alpha, Sodium channel protein type 3 subunit alpha (Nav1.1, Nav1.2, Nav1.3)

Voltage-gated sodium channels (VGSCs) of the Nav1.1, Nav1.2, and Nav1.3 subtypes are critical transmembrane proteins that conduct sodium ions across neuronal membranes in response to changes in membrane potential[1][3][7][9]. Each channel is formed by a large α-subunit (encoded by SCN1A, SCN2A, or SCN3A) with four homologous domains (DI–DIV), each comprising six transmembrane segments. The S4 segment in each domain acts as a voltage sensor; upon depolarization, the channel opens, allowing sodium influx and initiating the action potential. Rapid inactivation is mediated by an intracellular loop, crucial for repolarization and repetitive firing control[3][9]. These subtypes are primarily expressed in the central nervous system, with distinct but overlapping distribution patterns. Mutations in their genes are strongly linked to epilepsy, neurodevelopmental disorders, and other neurological syndromes[8]. Voltage-gated sodium channels are established therapeutic targets for anticonvulsants, local anesthetics, and antiarrhythmic drugs, but their high sequence homology poses challenges for isoform-selective drug development[2][4][7].

Other names

Nav1.1 (SCN1A)Nav1.2 (SCN2A)Nav1.3 (SCN3A)voltage-gated sodium channel alpha subunit (types I, II, III)VGSC

Blockade (inhibition) of sodium influx to prevent action potential firing Use-dependent blockade (preferential inhibition of overactive neurons) Modulation of channel inactivation states