title: Atrial natriuretic peptide inhibits nitric oxide synthesis in mouse macrophages.
abstract: The atrial natriuretic peptide (ANP) affects cardiovascular physiology, and, as has been suggested more recently, exerts immunomodulatory activities. In this context, we examined the effect of ANP on nitric oxide (NO) synthesis in murine bone marrow derived macrophages as well as in peritoneal macrophages. Cultured macrophages were stimulated with lipopolysaccharides (LPS 0.1-10 micrograms/ml) and NO synthesis was monitored by measuring increased concentrations of NO2 in the medium. In initial experiments employment of NG-monomethyl-L-arginine (L-NMMA) and dexamethasone, two specific inhibitors of nitric oxide synthase (NOS), confirmed the presence of inducible NOS activity in the cells. Exposure of cells to rat ANP99-126 in the range of 10(-8) to 10(-6) M significantly decreased LPS induced NO synthesis over 24 hours of incubation. Thus, ANP may alter macrophage function by affecting their nitric oxide synthesizing pathway.
authors.affiliation: Institute of Pharmacology, Toxicology and Pharmacy, University of Munich, Germany.
authors.forename: A M
authors.initials: AM
authors.lastname: Vollmar
authors.forename: R
authors.initials: R
authors.lastname: Schulz
mesh_terms: D000818:Animals; D001120:Arginine / Q000031:analogs & derivatives / Q000494:pharmacology; D009320:Atrial Natriuretic Factor / Q000494:pharmacology*; D002478:Cells, Cultured; D005260:Female; D008070:Lipopolysaccharides / Q000494:pharmacology; D008264:Macrophages / Q000378:metabolism*; D051379:Mice; D008807:Mice, Inbred BALB C; D009569:Nitric Oxide / Q000096:biosynthesis*; D051381:Rats; D019323:omega-N-Methylarginine
chemical_list: D008070:Lipopolysaccharides; D019323:omega-N-Methylarginine; D009569:Nitric Oxide; D009320:Atrial Natriuretic Factor; D001120:Arginine