Pharmacological research : the official journal of the Italian Pharmacological Society
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Non-steroidal anti-inflammatory drugs (NSAIDs) are frequently used as analgesics. Although the results of clinical studies indicate considerable disparity in the analgesic efficacy of NSAIDs, the pre-clinical models generally used for the study of nociception do not allow a clear distinction to be made between the analgesic properties of agents belonging to this family. As clinical pain is characterized by hyperalgesia, we evaluated the effects of NSAIDs with similar chemical structures but different selectivities for cyclo-oxygenase (COX)-1 and COX-2 in a new behavioural model of central hyperalgesia in rats. ⋯ However, only lornoxicam was fully effective for prevention of hyperalgesia. Our results indicate a dissociation between the anti-inflammatory and the anti-hyperalgesic activity of NSAIDs, where the latter seems to be more evident after the block of both COX-1 and COX-2. Finally, they suggest that our experimental model of thermal hindpaw hyperalgesia can be effectively utilized to assess the ability of different drugs to reduce central sensitization, and thus hyperalgesia.