Suppressive action of cobalt on exocytosis and respiratory burst in neutrophils.
Activation of exocytosis and respiratory burst in rabbit neutrophils by the chemotactic peptide fMet-Leu-Phe is inhibited by Co2+. Inhibition is antagonized by extracellular Ca2+ and is dependent on the time of preincubation of cells with Co2+ before addition of activator. Co2+ inhibits the enhancement of 45Ca association that occurs during activation with fMet-Leu-Phe. Interference with Ca2+ translocation across the plasma membrane by Co2+ is probably not the cause of inhibition of neutrophil activation, because activation in the absence of extracellular Ca2+ is inhibited by Co2+. Activation of neutrophils by phorbol myristate acetate is inhibited at higher Co2+ concentrations than activation by fMet-Leu-Phe. Inhibition of the superoxide production by Co2+ occurs both in the presence or in the absence of cytochalasin B. Fluorescence of neutrophils loaded with quin2 is diminished by Co2+, indicating that Co2+ had entered into the cytoplasm. The results are compatible with the view that Co2+ inhibits exocytosis and respiratory burst in neutrophils by an interaction with a Ca2+-dependent intracellular target.
Elferink
J G
JG
Department of Medical Biochemistry, Sylvius Laboratories, University of Leiden, The Netherlands.
Deierkauf
M
M
D000255:Adenosine Triphosphate / Q000378:metabolism; D000634:Aminoquinolines; D000818:Animals; D002118:Calcium / Q000494:pharmacology; D003035:Cobalt / Q000378:metabolism / Q000494:pharmacology*; D005089:Exocytosis / Q000187:drug effects*; D005456:Fluorescent Dyes; D009240:N-Formylmethionine Leucyl-Phenylalanine / Q000037:antagonists & inhibitors / Q000494:pharmacology; D009504:Neutrophils / Q000187:drug effects* / Q000378:metabolism / Q000502:physiology; D012119:Respiration / Q000187:drug effects*; D013481:Superoxides / Q000378:metabolism
D000634:Aminoquinolines; D005456:Fluorescent Dyes; D013481:Superoxides; D003035:Cobalt; D009240:N-Formylmethionine Leucyl-Phenylalanine; D000255:Adenosine Triphosphate; C035739:Quin2; D002118:Calcium