HYDROGEN PEROXIDE PRODUCTION STIMULATED BY N-FORMYL-METHIONYL-LEUCYL-PHENYLALANINE IN GUINEA PIG MACROPHAGES AND EFFECTS OF ANTI-INFLAMMATORY DRUGS AND LOCAL ANESTHETICS

Abstract

N-formyl-methionyl-leucyl-phenylalanine (FMLP)-stimulated hydrogen peroxide (H₂O₂) production in peritoneal macrophages and the effects of anti-inflammatory drugs and local anesthetics on it were electron cytochemically demonstrated using the cerium method. Resident peritoneal macrophages were harvested from adult male guinea pigs and treated with 5μg/ml cytochalasin B for 15min followed by an FMLP (1μM) treatment for 10min. The processed cells were incubated in a cerous medium in order to precipitate H₂O₂ moieties produced by the cells. FMLP induced cell aggregation, and the H₂O₂ production was seen on the plasma membrane sites where the cells had contacted. The reaction was markedly inhibited by p-benzoquinone and ethylenediamine-tetraacetate. Aspirin, indomethacin and lidocaine, but not dexamethasone, significantly reduced cell aggregation resulting in a decrease in the number of H₂O₂ productive cells. These results indicate that FMLP-stimulated H₂O₂ production in macrophages is initiated by calcium ions and inhibited by some anti-inflammatory drugs and local anesthetics in accord with reported physiological results, and that cell-cell contact is essential to H₂O₂ production.