Involvement of Spinal CB1 Cannabinoid Receptors on the Antinociceptive Effect of Celecoxib in Rat Formalin Test

Abstract

Background: The pivotal role of cyclooxygenase-2 (COX-2) inhibitors in inflammatory pain is well documented, but its mechanism is not entirely clear. Nonsteroidal anti-inflammatory drugs (NSAIDs) as inhibitors of COX could inhibit fatty acid amide hydrolase, the enzyme responsible for the metabolism of endocannabinoids. Therefore, it is expected that celecoxib administration (selective COX-2 inhibitor) preserve the increased level of endocannabinoids after noxious stimuli, which leads to more pain suppression. Objectives: This study was designed to evaluate the interaction between the intrathecally administered celecoxib in combination with rimonabant, a selective cannabinoid CB1 receptor antagonist/reverse agonist on the pain behavior induced by formalin test in rat. Materials and Methods: Male Wistar rats with inserted lumbar intrathecal catheters were randomly grouped and tested in blinded

Activation of Peripheral Cannabinoid Receptors Synergizes the Effect of Systemic Ibuprofen in a Pain Model in Rat

“…The intraplantar injection of ibuprofen or rofecoxib combined with anandamide yielded supra-additive synergism [ 17 , 18 ], while the systemic administration of WIN 55,212-2 plus ketorolac produced additive synergism [ 19 ]. Drugs such as selective COX2 inhibitors have also shown a synergistic effect when co-administered with cannabinoids [ 20 ].…”