Opiates suppress carrageenan-induced edema and hyperthermia at doses that inhibit hyperalgesia

摘要: This study determined whether opiates alter vascular components of inflammation (hyperthermia, edema and plasma extravasation) in addition to the suppression hyperalgesia. Rats were administered carrageenan into one hind paw saline other paw, followed by i.p. injection morphine (0.2–5.0 mg/kg) or at 60 min, testing 90 min after injections. Morphine produced a dose-dependent reduction carrageenan-induced hyperalgesia (17–53%), hyperthermia (39–53%) (24–36%). treatment did not temperatures contralateral saline-injected paws, indicating that opiate was confounded alterations systemic body temperature blood flow. The effects on stereospecific since levorphanol (1 mg/kg), but dextrorphan suppressed carrageenan-evoked hyperalgesia, edema. Pre-treatment with naltrexone (1.5 blocked 5 mg/kg dose sulfate In separate study, i.v. (2 reduced extravasation 41% (P < 0.01). administration resulted significantly greater increases withdrawal latencies inflamed (38–139%) than contralateral, saline-treated paws (4–19%). results indicate exert moderate, though significant, signs their mechanisms for this effect involve inhibition both vasodilation (as indicated decrease hyperthermia) permeability. addition, exhibit enhanced antinociceptive even when compared uninjured same animal.