An experimental paradigm, based on the microcrystalline sodium urate-induced arthritis pain model, was used to investigate the potential peripheral analgesic properties of a variety of opioid agonists. The response criteria were changes in behavioral profiles and pain-related behaviors over 60 min commencing 1 h after intraarticular injection. The testing system was used to determine the potential optimum dose of intraarticular application of morphine sulphate (1-3 mg), fentanyl citrate (0.5-3 mg), and buprenorphine hydrochloride (0.05-1 mg). None of the opioid analgesics used had any effect on pain behavior, and it was concluded that opioids with a high affinity for the mu receptor when injected intraarticularly were unlikely to be of use in the treatment or diagnosis of inflammatory arthritic pain in the strain of domestic fowl chosen.
Analgesia Analgesics