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

Voltage-gated sodium channels (VGSCs) are essential transmembrane proteins responsible for the rapid influx of sodium ions that initiates and propagates action potentials in excitable cells [1][5]. In the peripheral nervous system, specific alpha subunit subtypes, most notably Nav1.7 (encoded by SCN9A) and Nav1.8 (encoded by SCN10A), are predominantly expressed in nociceptive (pain-sensing) neurons [1][2][3]. Nav1.7 acts as a critical "threshold setter" for firing, while Nav1.8 sustains the action potential upstroke, particularly in cold or inflammatory conditions [3][4]. Genetic studies have firmly established their role in human pain; for instance, "gain-of-function" mutations in SCN9A cause severe pain syndromes like erythromelalgia, whereas "loss-of-function" mutations result in congenital insensitivity to pain [3]. Because of their localized expression in the periphery, these channels are high-value therapeutic targets for developing analgesics that lack the central side effects of opioids or the cardiac risks of non-selective blockers [4][5]. Current drug development efforts, such as the Nav1.8-selective inhibitor suzetrigine (VX-548), aim to provide potent pain relief by specifically blocking these channels in sensory neurons [5]. However, achieving high selectivity remains a challenge, as off-target inhibition of Nav1.5 in the heart or Nav1.1/1.2 in the brain can lead to significant safety concerns [3][4].

Other names

NavSodium channel protein type alpha subunitSCNNav1.7 (SCN9A)Nav1.8 (SCN10A)Sodium channel protein type 9 subunit alphaSodium channel protein type 10 subunit alpha

Selective or non-selective inhibition of the alpha subunit pore to prevent sodium ion influx, thereby suppressing the initiation and conduction of action potentials in peripheral sensory neurons [3][4].