The antinociceptive effects of a δ-opioid receptor agonist in mice with painful diabetic neuropathy: Involvement of heme oxygenase 1

Our results demonstrated that the subcutaneous administration of DPDPE inhibited the mechanical and thermal allodynia as well as the thermal hyperalgesia induced by diabetes in a dose-dependent manner. Moreover, while the antinociceptive effects produced by a low dose of DPDPE were enhanced by CORM-2 or CoPP co-treatments, the inhibitory effects produced by a high dose of DPDPE were completely reversed by the administration of an HO-1 inhibitor, SnPP, indicating the involvement of HO-1 in the antinociceptive effects produced by this DOR agonist during diabetic neuropathic pain in mice. In conclusion, this study shows that the administration of CORM-2 or CoPP combined with a DOR agonist could be an interesting strategy for the treatment of painful diabetic neuropathy.