Four main isoforms of NOSs have been recognized and located: a mitochondrial NOS (mtNOS) [69]; a neuronal NOS (nNOS), expressed in the postsynaptic terminal of neurons and Schwann cells; an endothelial NOS (eNOS), highly expressed in DRG consistently with allodynia, constitutively expressed and regulated by Ca2+/Calmodulin interaction; and an inducible NOS (iNOS), induced as a response to inflammation, trauma, or infection, which is not regulated by Ca2+, and highly expressed in the cytosol of glial cells [72,73,74]. The gene discussed is NOS1; the disease is infection.