Sodium channel protein type 2 subunit alpha and Sodium channel protein type 10 subunit alpha (NaV1.2/NaV1.8)

Voltage-gated sodium channels NaV1.2 and NaV1.8 are critical pore-forming proteins responsible for the rapid influx of sodium ions that initiates and propagates action potentials in excitable tissues. NaV1.2, encoded by the SCN2A gene, is primarily expressed in the central nervous system, particularly in the axons of excitatory neurons, where it plays a vital role in neuronal firing and synaptic integration. Mutations in SCN2A are linked to a spectrum of neurological conditions, including benign familial neonatal-infantile seizures, developmental and epileptic encephalopathies, and autism spectrum disorder. In contrast, NaV1.8, encoded by the SCN10A gene, is a tetrodotoxin-resistant channel predominantly localized in peripheral sensory neurons (nociceptors) and is a key mediator of inflammatory and neuropathic pain. While traditional sodium channel blockers like lidocaine and carbamazepine are non-selective and interact with both subtypes, modern drug discovery focuses on subtype-selective inhibitors to achieve specific therapeutic goals—such as treating epilepsy via NaV1.2 or managing pain via NaV1.8—while avoiding off-target effects like CNS toxicity or cardiac conduction issues. NaV1.8 is also expressed in the heart, where its inhibition or genetic variation can influence cardiac rhythm, adding a layer of complexity to its role as a therapeutic target.

Other names

SCN2ASCN10ANav1.2Nav1.8Sodium channel protein type II subunit alphaSodium channel protein type X subunit alphaPeripheral nerve sodium channel 3PN3Sensory neuron-specific sodium channelSNShPN3FEPS2

These channels are inhibited by drugs that bind to the alpha subunit, typically at the local anesthetic binding site within the pore or at allosteric sites on the voltage-sensing domains. This binding stabilizes the channel in its non-conducting inactivated state, thereby reducing the influx of sodium ions and suppressing the high-frequency repetitive firing of action potentials associated with pain or seizures.