m4v. Apple Iphone 6 with Retina Display Screen by applying the coupon code DREAM16H to get the price down to $349.99. Mobile Phone Accessories · Mobile Phone Cases.Dezocine attenuates opioid-induced hyperalgesia in a rat model of adjuvant-induced arthritis.
Parenteral morphine is effective in alleviating post-surgical and post-traumatic pain. However, its use is often limited by the occurrence of tolerance and opioid-induced hyperalgesia (OIH). Dezocine is a kappa opioid receptor agonist with reduced affinity for mu receptors, and has a lower affinity for the kappa receptor than for the opioid mu receptor. In this study, we investigated the effects of dezocine on pain thresholds in rats with adjuvant-induced arthritis (AIA). Arthritis was induced by injection of 1 mg of Mycobacterium butyricum. The severity of arthritis was graded according to a previously established scoring system. Spinal cord was isolated for nociceptive tests in normal rats. Nociceptive thresholds were assessed by the hot plate and tail-flick tests. The effect of dezocine on AIA was evaluated in groups of 10 rats. Each rat was treated with dezocine or saline by subcutaneous injection, twice daily for 2 days. On day 3, paw withdrawal latency (PWL) was measured at 30 min after intraperitoneal injection of 10 mg/kg fentanyl (an opioid receptor agonist), and the rats were killed for evaluation of spinal cord prostaglandin E2 (PGE2) level. Morphine hydrochloride was also administered subcutaneously for the same tests. Results demonstrated that the AIA rats developed severe arthritis, with a significantly increased PWL. Treatment with dezocine significantly decreased PWL in the AIA rats, indicating that dezocine attenuated the OIH. The PWL was similar to that in normal rats after dezocine treatment, and higher than that in AIA rats after morphine treatment. Moreover, the dezocine-induced OIH was reversed by a non-selective opioid antagonist, naloxone hydrochloride. The elevated levels of spinal cord PGE2 in the AIA rats were significantly reversed by dezocine. These results suggest that the kappa opioid receptor may be involved in the pathogenesis of OI
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