Following nerve trauma, a number of neurochemical changes that have been linked to neuropathic pain mechanisms (Hulse et al., 2012) occur within DRG neurons, including the neuronal injury marker activating transcription factor-3 (ATF-3) (Tsujino et al., 2000), neuropeptide Y (NPY) (Ma and Bisby, 1998), galanin (Hokfelt et al., 1987) and growth-associated protein-43 (GAP-43) (Sommervaille et al., 1991). This evidence concerns the gene NPY and injury.