title: Effect of cetirizine on antigen-induced tracheal contraction of passively sensitized guinea pigs.
abstract: BACKGROUND
  Cetirizine dihydrochloride (cetirizine), a potent histamine H1-receptor antagonist, has been developed as an anti-allergy drug.
  
  
  OBJECTIVE
  The anti-allergic effects and mechanism of cetirizine were studied using in vitro assay systems.
  
  
  METHODS
  We investigated the effect of cetirizine on antigen-induced contractions of isolated tracheal strips and on chemical mediator release from antigen-stimulated lung chips taken from passively sensitized guinea pigs. We examined the antigen-induced mobilization of Ca2+ in MC/9 mast cells sensitized with IgE.
  
  
  RESULTS
  Cetirizine inhibited the antigen-induced contraction of isolated guinea-pig trachea concentration dependently. Pyrilamine, another histamine H1-receptor antagonist, delayed the response but did not change the maximum amplitude. Cetirizine at the concentration of 3 microM also inhibited the antigen-induced release of histamine, leukotriene D4, and leukotriene E4 from guinea pig lung chips. Furthermore, it inhibited the antigen-induced Ca2+ increase in MC/9 mast cells, whereas pyrilamine did not.
  
  
  CONCLUSIONS
  These findings suggest that one anti-allergic mechanism of cetirizine may inhibit mediator release which is, at least partially, mediated by a decrease in the transient Ca2+ influx in mast cells.
authors.affiliation: First Department of Internal Medicine, Gunma University, School of Medicine, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Dobashi
authors.forename: K
authors.initials: K
authors.lastname: Iizuka
authors.forename: S
authors.initials: S
authors.lastname: Houjou
authors.forename: H
authors.initials: H
authors.lastname: Sakai
authors.forename: K
authors.initials: K
authors.lastname: Watanabe
authors.forename: M
authors.initials: M
authors.lastname: Mori
authors.forename: T
authors.initials: T
authors.lastname: Nakazawa
mesh_terms: D000818:Animals; D018926:Anti-Allergic Agents / Q000494:pharmacology*; D000941:Antigens; D002118:Calcium / Q000032:analysis; D002478:Cells, Cultured; D017332:Cetirizine / Q000494:pharmacology*; D006168:Guinea Pigs; D006632:Histamine / Q000276:immunology / Q000494:pharmacology; D006634:Histamine H1 Antagonists / Q000494:pharmacology; D006636:Histamine Release; D066298:In Vitro Techniques; D008168:Lung / Q000378:metabolism; D008297:Male; D008407:Mast Cells / Q000737:chemistry; D051379:Mice; D008807:Mice, Inbred BALB C; D009119:Muscle Contraction / Q000187:drug effects; D011738:Pyrilamine / Q000494:pharmacology; D014132:Trachea / Q000502:physiology*
chemical_list: D018926:Anti-Allergic Agents; D000941:Antigens; D006634:Histamine H1 Antagonists; D006632:Histamine; D011738:Pyrilamine; D002118:Calcium; D017332:Cetirizine