Influence of Y-20003, an analgesic agent, on the endogenous opioid peptide system in rats.
Changes of endogenous opioid peptide system by pain stimuli were examined using adjuvant-induced arthritic rats. Following the 5th day after adjuvant inoculation, met-enkephalin (ME)-like peptide content in plasma decreased, while after the 12th day, the peptide content increased in adrenal medulla. A significant correlationship was found between pain threshold and plasma ME-like peptide content. Y-20003, a new nonsteroidal agent without inhibition of prostaglandin biosynthesis, showed an analgesic effect which was significantly antagonized by naloxone or Win 44,441-3, suggesting that endogenous opioid peptide system may be involved in the analgesic mechanism of Y-20003.
D000313:Adrenal Medulla / Q000187:drug effects / Q000378:metabolism; D000634:Aminoquinolines / Q000494:pharmacology*; D000818:Animals; D001169:Arthritis, Experimental / Q000503:physiopathology; D004723:Endorphins / Q000502:physiology*; D004744:Enkephalin, Methionine / Q000097:blood / Q000378:metabolism*; D007700:Kinetics; D008297:Male; D010146:Pain / Q000503:physiopathology*; D051381:Rats; D011917:Rats, Inbred Lew
D000634:Aminoquinolines; D004723:Endorphins; C054869:Y 20003; D004744:Enkephalin, Methionine