title: Local increases of subcutaneous beta-endorphin immunoactivity at the site of thermal injury.
abstract: To examine interactions between exogenous opioid analgesia and endogenous opioid generation at a site of burn-induced tissue injury, we measured beta-endorphin (BE) and corticosterone (C) in aliquots of plasma and wound fluid withdrawn from subcutaneous wire mesh chambers beneath the site of a 3-5% surface area burn. After brief inhalational anesthesia at the time of thermal injury, rats received morphine (4 mg/kg, single dose), fentanyl (0.02 mg/kg hourly for 4 h), or no opioid. Systemic hormone responses and behavioral changes were minimal as expected for the minimal percentage burn. In all three groups intrachamber BE and C rose above baseline at 1, 2 and 4 h postburn, then returned to baseline at 24 h. Systemic opioid treatment produced analgesia (by tail flick latency testing) but did not reduce intrachamber hormone responses. Thus local BE and C responses at the site of thermal injury are regulated differently from systemic pituitary-adrenal responses.
authors.affiliation: Analgesic Peptide Research Unit, Department of Anesthesia, Massachusetts General Hospital, Harvard Medical School, Boston 02114.
authors.forename: M S
authors.initials: MS
authors.lastname: Cepeda
authors.forename: A W
authors.initials: AW
authors.lastname: Lipkowski
authors.forename: A
authors.initials: A
authors.lastname: Langlade
authors.forename: P F
authors.initials: PF
authors.lastname: Osgood
authors.forename: H P
authors.initials: HP
authors.lastname: Ehrlich
authors.forename: K
authors.initials: K
authors.lastname: Hargreaves
authors.forename: S K
authors.initials: SK
authors.lastname: Szyfelbein
authors.forename: D B
authors.initials: DB
authors.lastname: Carr
mesh_terms: D000701:Analgesics, Opioid / Q000494:pharmacology*; D000704:Analysis of Variance; D000818:Animals; D001826:Body Fluids / Q000378:metabolism; D002056:Burns / Q000150:complications / Q000276:immunology*; D003345:Corticosterone / Q000097:blood / Q000378:metabolism*; D008297:Male; D010146:Pain / Q000188:drug therapy / Q000209:etiology; D051381:Rats; D017207:Rats, Sprague-Dawley; D001615:beta-Endorphin / Q000097:blood / Q000187:drug effects / Q000378:metabolism*
chemical_list: D000701:Analgesics, Opioid; D001615:beta-Endorphin; D003345:Corticosterone