Kinetics of nitric oxide and hydrogen peroxide production and formation of peroxynitrite during the respiratory burst of human neutrophils

Abstract

Nitric oxide (.NO) release, oxygen uptake and hydrogen peroxide (H 2 O 2) production elicited by increasing phorbol 12‐myristate 13‐acetate (PMA) concentrations were measured in human neutrophils. Half‐maximal activities were sequentially elicited at about 0.0001–0.001 μg (.NO) and 0.001‐0.01 μg (H 2 O 2). At saturated PMA concentrations, .NO production, oxygen uptake and H 2 O 2 release were 0.56 ± 0.04, 3.32 ± 0.52 and 1.19±0.17 nmol · min−1 · 10 6 cells−1. .NO production accounts for about 30% of the total oxygen uptake. Luminol‐dependent chemiluminescence, reported to detect NO reactions in other inflammatory cells, was also half‐maximally activated at about 0.001‐0.01 μg . Preincubation with N G‐monomethyl‐l‐arginine (l‐NMMA) decreased O 2 uptake and .NO release but increased H 2 O 2 production, while superoxide dismutase (SOD) increased .NO detection by 30%. Chemiluminescence was also reduced by preincubation with l‐NMMA and/or SOD. The results indicate that .NO release is part of the integrated response of stimulated human neutrophils and that, in these cells, kinetics of ″NO and O 2 .− release favour the formation of other oxidants like peroxynitrite.