NaV1.9: a sodium channel linked to human pain.

The voltage-gated sodium channel Na(V)1.9 is preferentially expressed in nociceptors and has been shown in rodent models to have a major role in inflammatory and neuropathic pain. These studies suggest that by selectively targeting Na(V)1.9, it might be possible to ameliorate pain without inducing adverse CNS side effects such as sedation, confusion and addictive potential. Three recent studies in humans--two genetic and functional studies in rare genetic disorders, and a third study showing a role for Na(V)1.9 in painful peripheral neuropathy--have demonstrated that Na(V)1.9 plays an important part both in regulating sensory neuron excitability and in pain signalling. With this human validation, attention is turning to this channel as a potential therapeutic target for pain.