Tetrodotoxin-sensitive voltage-gated sodium channels (TTX-s Nav)

Tetrodotoxin-sensitive voltage-gated sodium channels (TTX-s Nav) are critical mediators of neuronal excitability in the peripheral nervous system, specifically within dorsal root ganglion (DRG) neurons. This group primarily includes the isoforms Nav1.1, Nav1.6, and Nav1.7, which are defined by their high affinity for the blocker tetrodotoxin (Catterall, 2000, Neuron). In the context of sensory signaling, Nav1.7 acts as a threshold-setter for action potentials, while Nav1.1 and Nav1.6 contribute to the propagation and firing frequency of nociceptive impulses (Dib-Hajj et al., 2013, Nature Reviews Neuroscience). These channels are essential for the transmission of pain signals from peripheral tissues to the spinal cord. Mutations in the genes encoding these channels, particularly SCN9A (Nav1.7), are directly linked to human pain disorders such as inherited erythromelalgia and congenital insensitivity to pain (Bennett & Woods, 2014, Lancet Neurology). Consequently, they are major therapeutic targets for the development of novel analgesics aimed at treating chronic and neuropathic pain. Drugs targeting these channels, such as local anesthetics and certain anticonvulsants, work by blocking the pore or stabilizing inactivated states to reduce hyperexcitability (Emery et al., 2016, Journal of Physiology). However, achieving isoform selectivity remains a significant challenge to avoid off-target effects in the central nervous system or motor pathways.

Other names

TTX-sensitive sodium channelsTTX-S VGSCsVoltage-gated sodium channel type 1 subunit alphaVoltage-gated sodium channel type 3 subunit alphaVoltage-gated sodium channel type 8 subunit alphaVoltage-gated sodium channel type 9 subunit alphaNav1.1Nav1.3Nav1.6Nav1.7SCN1ASCN3ASCN8ASCN9A

Inhibition of sodium ion influx through the channel pore or stabilization of the inactivated state, preventing neuronal depolarization and the transmission of pain signals (Emery et al., 2016, Journal of Physiology).