Potential role of the peroxidase-dependent metabolism of serotonin in lowering the polymorphonuclear leukocyte bactericidal function.
Serotonin (5-hydroxytryptamine, 5-HT) significantly and dose-dependently suppressed the luminol-enhanced chemiluminescence (CL) signal generated by polymorphonuclear leukocytes (PMN) activated with phorbol myristate acetate (PMA), but did not modify either lucigenin-enhanced CL or the reduction of superoxide dismutase-inhibitable cytochrome c. Moreover, stimulation of PMNs previously incubated with 5-HT resulted in a threefold increase in 5-HT equivalents bound to the proteins of PMN. The addition of catalase or sodium azide substantially reduced this binding. The present results suggest that 5-HT metabolism is mediated by H2O2 and myeloperoxidase (MPO) released by activated PMNs. Hence 5-HT could lower the bactericidal function of these cells by competition with hypochlorite formation from halides and MPO/H2O2.
Salman-Tabcheh
S
S
INSERM unité 58, Montpellier, France.
Guérin
M C
MC
Torreilles
J
J
D000166:Acridines; D001770:Blood Bactericidal Activity / Q000187:drug effects*; D002273:Carcinogens; D003574:Cytochrome c Group / Q000097:blood*; D006801:Humans; D006861:Hydrogen Peroxide / Q000378:metabolism; D008163:Luminescent Measurements; D018375:Neutrophil Activation; D009504:Neutrophils / Q000187:drug effects* / Q000378:metabolism; D010084:Oxidation-Reduction; D009195:Peroxidase / Q000097:blood*; D011485:Protein Binding; D012701:Serotonin / Q000097:blood*; D013481:Superoxides / Q000378:metabolism; D013755:Tetradecanoylphorbol Acetate
D000166:Acridines; D002273:Carcinogens; D003574:Cytochrome c Group; D013481:Superoxides; C033472:10,10'-dimethyl-9,9'-biacridinium; D012701:Serotonin; D006861:Hydrogen Peroxide; D009195:Peroxidase; D013755:Tetradecanoylphorbol Acetate