title: Melatonin increases the intensity of respiratory burst and prevents L-selectin shedding in human neutrophils in vitro.
abstract: Effects of melatonin priming of neutrophils and subsequent increase of phorbol 12-miristate 13-acetate stimulated respiratory burst were investigated on the modulation of L-selectin shedding and MAC-1 upregulation. Respiratory burst related H2O2 production and adhesion molecule expression were quantified by flow cytometry. Phorbol 12-miristate 13-acetate dose dependence of intracellular oxidation and adhesion molecule expression showed no relationship between respiratory burst intensity and MAC-1 expression or L-selectin shedding. Treatment of cells with 12.5 nM phorbol 12-miristate 13-acetate resulted in less than 20% of the respiratory burst response, however it induced 91.7% of total MAC-1 expression and 62.8% of L-selectin shedding. Melatonin priming experiments showed also no connection between the extent of respiratory burst and MAC-1 expression, however melatonin priming almost completely prevented L-selectin down-regulation elicited by phorbol 12-miristate 13-acetate, without affecting MAC-1 expression. It is suggested that melatonin may inhibit metalloproteases responsible for L-selectin cleavage.
authors.affiliation: "Nino Masera" Gerontology Research Department, I.N.R.C.A., Ancona, 60121, Italy.
authors.forename: R
authors.initials: R
authors.lastname: Recchioni
authors.forename: F
authors.initials: F
authors.lastname: Marcheselli
authors.forename: F
authors.initials: F
authors.lastname: Moroni
authors.forename: R
authors.initials: R
authors.lastname: Gáspár
authors.forename: S
authors.initials: S
authors.lastname: Damjanovich
authors.forename: C
authors.initials: C
authors.lastname: Pieri
mesh_terms: D004305:Dose-Response Relationship, Drug; D006801:Humans; D006861:Hydrogen Peroxide / Q000097:blood; D066298:In Vitro Techniques; D007700:Kinetics; D019041:L-Selectin / Q000096:biosynthesis / Q000097:blood*; D016177:Macrophage-1 Antigen / Q000096:biosynthesis / Q000097:blood; D008550:Melatonin / Q000494:pharmacology*; D009504:Neutrophils / Q000187:drug effects / Q000502:physiology*; D016897:Respiratory Burst / Q000187:drug effects* / Q000502:physiology; D020112:Rhodamine 123; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology
chemical_list: D016177:Macrophage-1 Antigen; D019041:L-Selectin; D020112:Rhodamine 123; D006861:Hydrogen Peroxide; D008550:Melatonin; D013755:Tetradecanoylphorbol Acetate