title: Regulation of endothelin receptors by nitric oxide in cultured rat vascular smooth muscle cells.
abstract: Two important mediators of endothelium-dependent regulation of vascular smooth muscle tone and proliferation are nitric oxide (NO) and endothelin (ET-1). An imbalance between NO and ET-1 may contribute to the alterations in vascular tone characteristic of cardiovascular disease. The objective of this study was to determine whether NO regulates ET receptors in cultured rat superior mesenteric artery vascular smooth muscle cells (RVSMC). Chronic treatment of quiescent RVSMC with any one of three chemically dissimilar NO-generating drugs, S-nitroso-N-acetyl penicillamine (SNAP), sodium nitroprusside (SNP), and isosorbide dinitrate (ISDN) produced a significant dose- and time-dependent increase in the number of ET-A receptors, while concomitantly increasing the affinity of ET-1 for this receptor. This effect was mimicked by both 8-bromo-cGMP and 8-bromo-cAMP. The requirement of both protein and RNA synthesis and activation of a cAMP-dependent protein kinase (A-kinase) was demonstrated following inhibition of this regulation by cycloheximide, actinomycin D and KT5720 (a specific A-kinase inhibitor), respectively. In addition, the cytokine interleukin 1 beta (IL-1 beta) which induced NOS activity with subsequent NO synthesis in vascular smooth muscle, also caused a similar upregulation of ET receptors. This effect was attenuated in the presence of the specific NOS inhibitor, L-NAME. To assess the possible functional consequences of this NO-mediated upregulation, the effect of SNAP pretreatment on isolated vessel reactivity was determined. In both superior mesenteric artery and thoracic aorta rings, SNAP pretreatment caused a significant increase in the maximal force of contraction to ET-1. Collectively, these data suggest that NO regulates ET-A receptors in vitro through a cGMP-dependent mechanism via activation of the cAMP-dependent protein kinase. We conclude that a similar interaction between NO and ET-1 may be operational in vivo.
authors.affiliation: The Johns Hopkins Medical Institutions, Department of Surgery, Baltimore, Maryland, 21287 USA.
authors.forename: E M
authors.initials: EM
authors.lastname: Redmond
authors.forename: P A
authors.initials: PA
authors.lastname: Cahill
authors.forename: R
authors.initials: R
authors.lastname: Hodges
authors.forename: S
authors.initials: S
authors.lastname: Zhang
authors.forename: J V
authors.initials: JV
authors.lastname: Sitzmann
mesh_terms: D015124:8-Bromo Cyclic Adenosine Monophosphate / Q000494:pharmacology; D000818:Animals; D009320:Atrial Natriuretic Factor / Q000494:pharmacology; D002478:Cells, Cultured; D017868:Cyclic AMP-Dependent Protein Kinases / Q000502:physiology; D006152:Cyclic GMP / Q000031:analogs & derivatives / Q000494:pharmacology; D016232:Endothelins / Q000378:metabolism*; D066298:In Vitro Techniques; D007375:Interleukin-1 / Q000494:pharmacology; D007548:Isosorbide Dinitrate / Q000494:pharmacology; D008297:Male; D017538:Mesenteric Artery, Superior; D009131:Muscle, Smooth, Vascular / Q000166:cytology / Q000378:metabolism*; D009569:Nitric Oxide / Q000502:physiology*; D019001:Nitric Oxide Synthase / Q000096:biosynthesis / Q000378:metabolism; D009599:Nitroprusside / Q000494:pharmacology; D010396:Penicillamine / Q000031:analogs & derivatives / Q000494:pharmacology; D011500:Protein Synthesis Inhibitors / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D017466:Receptors, Endothelin / Q000096:biosynthesis* / Q000378:metabolism; D026423:S-Nitroso-N-Acetylpenicillamine; D015854:Up-Regulation
chemical_list: D016232:Endothelins; D007375:Interleukin-1; D011500:Protein Synthesis Inhibitors; D017466:Receptors, Endothelin; D009599:Nitroprusside; D015124:8-Bromo Cyclic Adenosine Monophosphate; C016276:8-bromocyclic GMP; D009569:Nitric Oxide; D026423:S-Nitroso-N-Acetylpenicillamine; D009320:Atrial Natriuretic Factor; D019001:Nitric Oxide Synthase; D017868:Cyclic AMP-Dependent Protein Kinases; D010396:Penicillamine; D006152:Cyclic GMP; D007548:Isosorbide Dinitrate