title: Morphine-induced enhancement in the granulocyte response to thioglycollate administration in the rat.
abstract: The present study determined the pharmacological effects of acute morphine treatment on the granulocyte phase of the peritoneal inflammatory response to thioglycollate (TG) in rats. Dual-color flow cytometry using anti-CD11b/c-PE mAb in combination with HIS48-FITC mAb allowed for the determination of morphine's effects on 4 inflammatory cell subsets: CD11b/c(+)HIS48med granulocytes; CD11b/c(hi)HIS48neg/lo activated macrophages; CD11b/c(-)HIS48(-) lymphocytes; and CD11b/c(+)HIS48hi cells (a monocyte/macrophage and granulocyte subset). Morphine produced a dose-dependent increase in a select subset of inflammatory peritoneal cells, the CD11b/c(+)HIS48med granulocytes. The effect of morphine was time-dependent, with significant effects first apparent at 4 hr after TG, but the administration of morphine 1 hr before or simultaneously with TG produced a similar increase in CD11b/c(+)HIS48med granulocytes. Naltrexone completely antagonized the morphine-induced increase in CD11b/c(+)HIS48med granulocytes. Collectively, these studies show that a single administration of morphine produces a time-dependent, dose-dependent, opioid receptor-mediated enhancement in the peritoneal granulocyte response to TG.
authors.affiliation: Department of Psychology and Curriculum in Neurobiology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA. kfecho@email.unc.edu
authors.forename: Karamarie
authors.initials: K
authors.lastname: Fecho
authors.forename: Donald T
authors.initials: DT
authors.lastname: Lysle
mesh_terms: D000818:Animals; D004305:Dose-Response Relationship, Drug; D006098:Granulocytes / Q000187:drug effects* / Q000276:immunology / Q000378:metabolism; D008297:Male; D009020:Morphine / Q000494:pharmacology*; D010529:Peritoneal Cavity / Q000502:physiology; D010538:Peritonitis / Q000139:chemically induced / Q000276:immunology / Q000378:metabolism; D051381:Rats; D011917:Rats, Inbred Lew; D013864:Thioglycolates / Q000633:toxicity*
chemical_list: D013864:Thioglycolates; D009020:Morphine