title: Natriuretic peptide receptor-B (guanylyl cyclase-B) mediates C-type natriuretic peptide relaxation of precontracted rat aorta.
abstract: The most potent known agonist for the natriuretic peptide receptor-B (NPR-B)/guanylyl cyclase-B is C-type natriuretic peptide (CNP). A homologous ligand-receptor system consists of atrial natriuretic peptide (ANP) and NPR-A/guanylyl cyclase-A. A third member of this family is NPR-C, a non-guanylyl cyclase receptor. Monoclonal antibodies were raised against NPR-B by immunizing mice with a purified receptor-IgG fusion protein consisting of the extracellular domain of NPR-B and the Fc portion of human IgG-gamma 1. One monoclonal antibody, 3G12, did not recognize NPR-A or NPR-C and bound to human and rat NPR-B. CNP binding to NPR-B and stimulation of cGMP synthesis were inhibited by 3G12. With cells isolated from either the media or adventitia layers of rat thoracic aorta, 3G12 did not interfere with ANP-stimulated cGMP synthesis, but it inhibited CNP-stimulated cGMP levels in cells from both layers. CNP (IC50 = 10 nM) and ANP (IC50 = 1 nM) caused relaxation of phenylephrine-contracted rat aortic rings. 3G12 caused a marked increase in the IC50 for CNP, from 10 nM to 140 nM, but failed to affect ANP-mediated relaxation. Therefore, our results for the first time demonstrate that CNP relaxes vascular smooth muscle by virtue of its binding to NPR-B.
authors.affiliation: Department of Pharmacology and Toxicology, Medical College of Wisconsin, Milwaukee 53226.
authors.forename: J G
authors.initials: JG
authors.lastname: Drewett
authors.forename: B M
authors.initials: BM
authors.lastname: Fendly
authors.forename: D L
authors.initials: DL
authors.lastname: Garbers
authors.forename: D G
authors.initials: DG
authors.lastname: Lowe
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000494:pharmacology; D001011:Aorta / Q000502:physiology*; D002460:Cell Line; D006162:Guanylate Cyclase / Q000037:antagonists & inhibitors / Q000378:metabolism / Q000502:physiology*; D006801:Humans; D066298:In Vitro Techniques; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D009126:Muscle Relaxation / Q000502:physiology; D020098:Natriuretic Peptide, C-Type; D011485:Protein Binding; D011506:Proteins / Q000378:metabolism / Q000502:physiology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D017461:Receptors, Atrial Natriuretic Factor / Q000037:antagonists & inhibitors / Q000378:metabolism / Q000502:physiology*
chemical_list: D000911:Antibodies, Monoclonal; D011506:Proteins; D020098:Natriuretic Peptide, C-Type; D006162:Guanylate Cyclase; D017461:Receptors, Atrial Natriuretic Factor; C073616:atrial natriuretic factor receptor C