Respiratory burst of Japanese eel neutrophils

Japanese eel (Anguilla japonica) neutrophils underwent a striking increase in oxygen consumption by stimulation, which is usually called respiratory burst. This increased uptake of oxygen was insensitive to mitochondrial respiration inhibitor such as potassium cyanide. Superoxide was detected during the respiratory burst by measuring chemiluminescence (CL) enhanced by 2-methyl-6-phenyl-3,7-dihydro-imidazo[1,2-a]pyrazine-3-one (CLA) which is highly specific and sensitive to superoxide. EDTA blocked while EGTA stilumated CLA-enhanced CL. These characters of the respiratory burst suggest that Japanese eel neutrophils have NADPH oxidase-like activity similar to the mammalian NADPH oxidase. Sodium azide, an inhibitor of myeloperoxidase (MPO) activity, did not affect luminol-enhanced CL, which is thought to be dependent on hypochlorous acid (HOCl) produced by catalysis of MPO. It is suggested that Japanese eel neutrophils do not generate HOCl during the respiratory burst because of lacking MPO in cytoplasm.