Increase in the threshold of a nociceptive test induced by naloxone in morphine-tolerant rats.
The effects of various doses of naloxone (3-1000 micrograms/kg i.v.) on the vocalization threshold elicited by pressure on the paw were evaluated in rats chronically treated with high doses of morphine. In addition to the well known precipitation of withdrawal induced by naloxone, an unexpected dose-related increase in the vocalization threshold was observed.
D000818:Animals; D001169:Arthritis, Experimental / Q000503:physiopathology; D004361:Drug Tolerance; D008297:Male; D009020:Morphine / Q000008:administration & dosage*; D009270:Naloxone / Q000008:administration & dosage*; D010146:Pain / Q000503:physiopathology*; D051381:Rats; D011919:Rats, Inbred Strains; D012684:Sensory Thresholds; D013375:Substance Withdrawal Syndrome / Q000503:physiopathology; D014828:Vocalization, Animal / Q000502:physiology
D009270:Naloxone; D009020:Morphine