title: Nitric oxide modulates cardiac and mast cell anaphylaxis.
abstract: Anaphylaxis in the isolated guinea-pig heart was associated with a sudden release of histamine with a long-lasting release of nitrite (NO2-), an oxidation product of NO. NG-monomethyl-L-arginine (MeArg, 300 microM) increased the severity of cardiac anaphylaxis, as shown by the decrease in the coronary flow and by a prolonged duration of antigen-induced arrhythmias. Concomitantly, MeArg increased the release of histamine while decreasing the release of nitrite. Sodium nitroprusside (NaNP, 10(-5)-10(-4) M) reduced the severity of cardiac anaphylaxis by increasing coronary flow and shortening the duration of antigen-induced arrhythmias. Concomitantly, NaNP decreased the release of histamine while increasing the release of nitrite. In mast cells isolated from actively sensitized guinea-pigs, the release of histamine elicited by specific antigen was increased by MeArg and decreased by NaNP. In conclusion, endogenous and exogenous NO antagonizes the effect of vasoconstrictor mediators released after antigen challenge and plays a protective role in anaphylactic reactions "in vitro".
authors.affiliation: Department of Preclinical and Clinical Pharmacology, University of Florence, Italy.
authors.forename: E
authors.initials: E
authors.lastname: Masini
authors.forename: F
authors.initials: F
authors.lastname: Gambassi
authors.forename: M G
authors.initials: MG
authors.lastname: Di Bello
authors.forename: L
authors.initials: L
authors.lastname: Mugnai
authors.forename: S
authors.initials: S
authors.lastname: Raspanti
authors.forename: P F
authors.initials: PF
authors.lastname: Mannaioni
mesh_terms: D000594:Amino Acid Oxidoreductases / Q000037:antagonists & inhibitors; D000707:Anaphylaxis / Q000503:physiopathology*; D000818:Animals; D001120:Arginine / Q000031:analogs & derivatives / Q000494:pharmacology; D003326:Coronary Circulation / Q000187:drug effects; D006168:Guinea Pigs; D006321:Heart / Q000187:drug effects / Q000503:physiopathology*; D006636:Histamine Release / Q000187:drug effects; D066298:In Vitro Techniques; D008297:Male; D008407:Mast Cells / Q000187:drug effects / Q000502:physiology*; D019331:NG-Nitroarginine Methyl Ester; D009569:Nitric Oxide / Q000037:antagonists & inhibitors / Q000378:metabolism / Q000502:physiology*; D019001:Nitric Oxide Synthase; D009599:Nitroprusside / Q000494:pharmacology; D010047:Ovalbumin / Q000276:immunology
chemical_list: D009599:Nitroprusside; D009569:Nitric Oxide; D010047:Ovalbumin; D001120:Arginine; D019001:Nitric Oxide Synthase; D000594:Amino Acid Oxidoreductases; D019331:NG-Nitroarginine Methyl Ester