• Takehiro Ochi, Yoshitaka Ohkubo, and Seitaro Mutoh.
• Department of Immunology and Inflammation, Medicinal Biology Research Laboratories, Fujisawa Pharmaceutical Co., Ltd., 1-6, Kashima 2-chome, Yodogawa-ku, Osaka, 532-8514, Japan. takehiro_ochi@po.fujisawa.co.jp
• Neurosci. Lett. 2003 Oct 16; 350 (1): 29-32.

AbstractWe investigated the anti-hyperalgesic effect of FR140423, 3-(difluoromethyl)-1-(4-methoxyphenyl-5-[4-(methylsulfinyl)phenyl]pyrazole, in a rat model of postoperative pain. Oral administration of FR140423 at doses between 1 and 100 mg/kg after surgery dose dependently attenuated the punctate mechanical hyperalgesia caused by an incision of the plantar surface of the hind paw with an ED50 value of 59 mg/kg. The anti-hyperalgesic effect of systematically administered FR140423 was blocked by naloxone, a non-selective opioid receptor antagonist. Furthermore, the delta-opioid receptor antagonist naltrindole (0.2 mg/kg) reversed anti-hyperalgesia induced by FR140423. Naloxonazine and nor-binaltorphimine failed to antagonize the anti-hyperalgesic effect of FR140423. The action of FR140423 differs from the naloxonazine-reversible anti-hyperalgesia induced by morphine. The present findings suggest that delta-opioid systems play a role in the rat anti-hyperalgesia produced by FR140423 for postoperative pain characterized by mechanical hyperalgesia.

30 keywords...

hide…