The role of Nav1.9 channel in the development of neuropathic orofacial pain associated with trigeminal neuralgia

Background: Trigeminal neuralgia is accompanied by severe mechanical, thermal and chemical hypersensitivity of the orofacial area innervated by neurons of trigeminal ganglion (TG). We examined the role of the voltage-gated sodium channel subtype Na(v)1.9 in the development of trigeminal neuralgia. Results: We found that Na(v)1.9 is required for the development of both thermal and mechanical hypersensitivity induced by constriction of the infraorbital nerve (CION). The CION model does not induce change on Na(v)1.9 mRNA expression in the ipsilateral TG neurons when evaluated 9 days after surgery. Conclusions: These results demonstrate that Na(v)1.9 channels play a critical role in the development of orofacial neuropathic pain. New routes for the treatment of orofacial neuropathic pain focussing on regulation of the voltage-gated Na(v)1.9 sodium channel activity should be investigated.