title: Histamine modulates mast cell degranulation through an indirect mechanism in a model IgE-mediated reaction.
abstract: Histamine is released in inflammatory reactions and exerts an immunoregulatory function on cells present in the microenvironment. In this study, we compared the effect of histamine on degranulation of mast cells derived from animals bearing a parasitic infection with those from uninfected animals. Peritoneal mast cells (PMC) were obtained 24 days after infection of Wistar rats with Toxocara canis. The degree of degranulation was assessed either morphologically or by measuring the release of beta-hexosaminidase and TNF-alpha. Non-purified PMC or mast cells immunomagnetically purified with mAb AA4 were used. An increase in degranulation of non-purified mast cells from infected animals was observed after incubation with histamine in vitro or when histamine was injected into the peritoneal cavity. When a purified mast cell population was used, this effect was no longer observed. Supernatants from spleen cells stimulated with histamine induced degranulation of purified mast cells, and again, this was potentiated with PMC from infected animals. However, when supernatants from peritoneal macrophages similarly stimulated were used, a reduction in the degranulation of PMC from infected animals was observed. Our results suggest that histamine may act as a regulator of mast cell degranulation, thus modulating inflammatory responses due to infection with certain parasites.
authors.affiliation: Universidade de São Paulo (USP), Departamento de Análises Clínicas, Toxicológicas e Bromatológicas, Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Brasil.
authors.forename: Daniela
authors.initials: D
authors.lastname: Carlos
authors.forename: Anderson
authors.initials: A
authors.lastname: Sá-Nunes
authors.forename: Lúcia
authors.initials: L
authors.lastname: de Paula
authors.forename: Camila
authors.initials: C
authors.lastname: Matias-Peres
authors.forename: Maria Célia
authors.initials: MC
authors.lastname: Jamur
authors.forename: Constance
authors.initials: C
authors.lastname: Oliver
authors.forename: Magda Fraguas
authors.initials: MF
authors.lastname: Serra
authors.forename: Marco Aurélio
authors.initials: MA
authors.lastname: Martins
authors.forename: Lúcia Helena
authors.initials: LH
authors.lastname: Faccioli
mesh_terms: D000818:Animals; D015550:Cell Degranulation / Q000187:drug effects / Q000276:immunology*; D002927:Cimetidine / Q000494:pharmacology; D005260:Female; D005434:Flow Cytometry; D006632:Histamine / Q000276:immunology* / Q000494:pharmacology; D006634:Histamine H1 Antagonists / Q000494:pharmacology; D006635:Histamine H2 Antagonists / Q000494:pharmacology; D007073:Immunoglobulin E / Q000097:blood / Q000276:immunology*; D007150:Immunohistochemistry; D008264:Macrophages / Q000187:drug effects / Q000276:immunology; D008407:Mast Cells / Q000166:cytology / Q000276:immunology / Q000469:parasitology / Q000502:physiology*; D009569:Nitric Oxide / Q000096:biosynthesis / Q000276:immunology; D010529:Peritoneal Cavity / Q000166:cytology; D011738:Pyrilamine / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D017166:Toxocara canis / Q000276:immunology*; D014120:Toxocariasis / Q000097:blood / Q000276:immunology* / Q000469:parasitology; D014409:Tumor Necrosis Factor-alpha / Q000276:immunology; D001619:beta-N-Acetylhexosaminidases / Q000276:immunology; D003189:p-Methoxy-N-methylphenethylamine / Q000494:pharmacology
chemical_list: D006634:Histamine H1 Antagonists; D006635:Histamine H2 Antagonists; D014409:Tumor Necrosis Factor-alpha; D009569:Nitric Oxide; D007073:Immunoglobulin E; D003189:p-Methoxy-N-methylphenethylamine; D002927:Cimetidine; D006632:Histamine; D001619:beta-N-Acetylhexosaminidases; D011738:Pyrilamine