Based on these findings and that UFP-512 exerts its cytoprotective effects in cell cultures via activation of the Nrf2/HO–1/NQO1 pathway (Cao S. et al., 2015), we evaluated whether the inhibitory effects of this DOR agonist during chronic inflammatory or neuropathic pain were also produced via activation of this antioxidant pathway and/or reduction of the inflammatory and nociceptive responses implicated in the maintenance of chronic pain. Here, NFE2L2 is linked to Pain.