title: Interaction between curcumin and opioid system in the formalin test of rats.
abstract: In this study, the effect of curcumin on the formalin-induced pain was investigated in rats. Interaction between curcumin and opioid system using morphine and naloxone was also examined. A biphasic pain response was induced after intraplantar injection of formalin (50 microL, 1%). Curcumin, morphin and naloxone had no effect on the early phase of pain. Late phase of pain was suppressed by curcumin at the doses of 100 and 200 mg kg(-1) body weigh. Morphine (1 mg kg(-1) BW) reduced, whereas naloxone (1 mg kg(-1) BW) did not affect the late phase of pain. Currcumin did not influence the morphine-induced antinociception, but reversed the effect of naloxone on pain. Present findings indicate that curcumin may produce antinociception by activation of both opioid and non opioid mechanisms of pain.
authors.affiliation: Department of Food Hygiene, College of Veterinary Medicine, Urmia University, Urmia, Iran.
authors.forename: Hossein
authors.initials: H
authors.lastname: Tajik
authors.forename: Esmaeal
authors.initials: E
authors.lastname: Tamaddonfard
authors.forename: Nasrin
authors.initials: N
authors.lastname: Hamzeh-Gooshchi
mesh_terms: D000701:Analgesics, Opioid / Q000378:metabolism; D000818:Animals; D000970:Antineoplastic Agents / Q000378:metabolism*; D003474:Curcumin / Q000378:metabolism*; D008297:Male; D009020:Morphine / Q000378:metabolism; D009270:Naloxone / Q000378:metabolism; D010146:Pain / Q000503:physiopathology*; D010147:Pain Measurement; D051381:Rats; D017208:Rats, Wistar; D011957:Receptors, Opioid / Q000378:metabolism*
chemical_list: D000701:Analgesics, Opioid; D000970:Antineoplastic Agents; D011957:Receptors, Opioid; D009270:Naloxone; D009020:Morphine; D003474:Curcumin