Sodium butyrate and its synthetic amide derivative modulate nociceptive behaviors in mice

In the present study we investigated the role of sodium butyrate (butyrate), and its more palatable derivative, the N-(1-carbamoyl-2-phenyl-ethyl) butyramide (FBA), in animal models of acute and chronic pain. We found that oral administrations of butyrate (10-200 mg/Kg) or equimolecular FBA (21.2-424 mg/Kg) reduced visceral pain in a dose- and time-dependent manner. Both drugs were also effective in the formalin test, showing an antinociceptive effect. This analgesic effect was blocked by glibenclamide, suggesting the involvement of ATP-dependent K+ channels. Moreover, following repeated administration butyrate (100-200 mg/Kg) and FBA (212-424 mg/Kg) retained their analgesic properties in a model of neuropathic pain, reducing mechanical and thermal hyperalgesia in the chronic constriction injury (CCI) model. The involvement of peroxisome proliferator-activated receptor (PPAR) -alpha and -gamma for the analgesic effect of butyrate was also investigated by using PPAR-alpha null mice or the PPAR-gamma antagonist GW9662. Western blot analysis, confirmed the role of peroxisome receptors in butyrate effects, evidencing the increase of PPAR-alpha and -gamma expression, associated to the reduction of inflammatory markers (COX-2, iNOS, TNF-alpha and cFOS). In conclusion, we describe the role of butyrate-based drugs in pain, identifying different and converging non-genomic and genomic mechanisms of action, which cooperate in nociception maintenance. (C) 2015 Published by Elsevier Ltd.