Opioid antagonism in fentanyl antinociception experimental

Among the most commonly used drugs to reduce pain and inflammation are nonsteroidal anti-inflammatory (NSAIDs) opioids. Opioids a wide group of including fentanyl fully synthetic opioid that is more potent morphine. The aim present study was evaluate antinociception in two murine tests, acetic acid writhing (WT) formalin hind paw (FHP). Likewise, involvement opioids antagonists: naltrexone, naltrindole nor-binaltorphimine induced activity estimated. antinociceptive evaluated from dose-response curves. intraperitoneal administration dose related effects with different potencies both tests. data revealed significant decrease analgesic effect by action WT FHP tests exception WT. antagonist reducing efficacy could possibly be other multiple mechanisms added inhibition activation MOR, DOR, KOR receptors. This demonstrates there functional interaction modulatory between assays paw. modulation seems mediated fentanyl. These results suggest than able effective models nociception inflammatory pain.