An antioxidant agent prevents NO2-induced inhibition of mast cell mediator release: evidence that the mechanism involves free radicals.
Previously we established that in vitro NO2 exposure induced inhibition of histamine release from rat peritoneal mast cells (PMC) stimulated with secretagogues such as compound 48/80 or substance P. To further explore the effects of NO2 exposure on mast cells, we investigated whether the addition of an antioxidant agent, 2-mercaptoethanol (2-ME), can prevent NO2-induced inhibition of mediator release from PMC. Histamine release from 5 ppm NO2-exposed PMC stimulated with 10 and 20 microM substance P was significantly inhibited compared with that from the controls. beta-Hexosaminidase release from 5 ppm NO2-exposed PMC stimulated with 20 microM substance P was also significantly inhibited. However, the inhibition of both histamine and beta-hexosaminidase release from exposed PMC was diminished by the addition of 5 mM 2-ME during NO2 exposure. Although IgE-mediated histamine release from NO2 exposed PMC was markedly inhibited, the addition of 5 mM 2-ME during NO2 exposure induced no inhibition of histamine release. These results suggest a possible relationship between NO2-induced inhibition of mast cell mediator release and production of free radicals by the action of NO2.
National Institute for Environmental Studies, Ibaraki, Japan.
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Fujimaki
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Shiraishi
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Wakamori
D000818:Animals; D000888:Antibodies, Anti-Idiotypic / Q000276:immunology; D004305:Dose-Response Relationship, Drug; D005609:Free Radicals; D006636:Histamine Release / Q000187:drug effects; D007073:Immunoglobulin E / Q000276:immunology; D008297:Male; D008407:Mast Cells / Q000187:drug effects*; D008623:Mercaptoethanol / Q000494:pharmacology*; D009585:Nitrogen Dioxide / Q000009:adverse effects / Q000037:antagonists & inhibitors*; D051381:Rats; D011919:Rats, Inbred Strains; D013373:Substance P / Q000494:pharmacology; D001619:beta-N-Acetylhexosaminidases / Q000378:metabolism
D000888:Antibodies, Anti-Idiotypic; D005609:Free Radicals; C026408:anti-IgE antibodies; D013373:Substance P; D007073:Immunoglobulin E; D008623:Mercaptoethanol; D001619:beta-N-Acetylhexosaminidases; D009585:Nitrogen Dioxide