title: Identification and localization of adrenomedullin-storing cardiac mast cells.
abstract: Adrenomedullin (AM), a potent vasodilatory hypotensive peptide, is expressed in the heart, where it is known to play a protective action. Light-microscopy immunocytochemistry (ICC) demonstrated the presence of AM immunoreactivity not only in the coronary-vessel wall and ventricular myocytes of the human and rat heart, but also in sparse voluminous cells located in the perivascular space. These cells displayed the same location of toluidine blue-positive mast cells, and electron microscopy ICC showed AM-immunogold staining over the granules of rat cardiac mast cells. The incubation of rat left ventricle fragments with the mast-cell histamine releaser compound 48/80 evidenced groups of AM-positive cells undergoing degranulation and caused an increase of approximately 50% in the AM concentration in the incubation medium. Collectively, our findings provide evidence that at least a subset of cardiac mast cells are able to synthesize and store AM, and upon stimulation to release it near coronary arterioles and venules.
authors.affiliation: Department of Human Anatomy and Physiology, Section of Anatomy, School of Medicine, University of Padua, I-35121 Padua, Italy.
authors.forename: Anna S
authors.initials: AS
authors.lastname: Belloni
authors.forename: Lucia
authors.initials: L
authors.lastname: Petrelli
authors.forename: Diego
authors.initials: D
authors.lastname: Guidolin
authors.forename: Renzo
authors.initials: R
authors.lastname: De Toni
authors.forename: Sergio
authors.initials: S
authors.lastname: Bova
authors.forename: Raffaella
authors.initials: R
authors.lastname: Spinazzi
authors.forename: Gino
authors.initials: G
authors.lastname: Gerosa
authors.forename: Gian Paolo
authors.initials: GP
authors.lastname: Rossi
authors.forename: Gastone G
authors.initials: GG
authors.lastname: Nussdorfer
mesh_terms: D053607:Adrenomedullin; D000818:Animals; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D008407:Mast Cells / Q000737:chemistry* / Q000187:drug effects / Q000648:ultrastructure; D008854:Microscopy, Electron; D009206:Myocardium / Q000737:chemistry* / Q000166:cytology; D010455:Peptides / Q000032:analysis*; D051381:Rats; D017207:Rats, Sprague-Dawley; D003189:p-Methoxy-N-methylphenethylamine / Q000494:pharmacology
chemical_list: D010455:Peptides; D053607:Adrenomedullin; D003189:p-Methoxy-N-methylphenethylamine