title: Cellular control of nitric oxide synthase expression and activity in rat cardiomyocytes.
abstract: Potential ortho- and pathophysiological roles for nitric oxide synthases (NOS) in cardiac functions have been and are continuing to be described. However, cellular signaling mechanisms controlling nitric oxide (NO) production in the heart remain obscure. The aim of this study was to investigate signaling mechanisms involved in regulation of NOS expression and NO generation in cardiomyocytes. Using immunocytochemical methods in conjunction with western blotting, we have found that cultured neonatal rat cardiomyocytes express constitutively all three NOS isoforms targeted predominantly to the particulate component of cardiomyocytes - mitochondria and along contractile fibers, as well as along plasma membrane including T-tubules. Biochemical assay of NO generation has shown that exposure of cultured neonatal rat cardiac cells to isoproterenol (beta-adrenergic stimulation), iloprost [stable prostaglandin I(2) (PGI(2)) analogue], as well as inflammatory cytokines and dibutyryl adenosine-3',5'-monophosphate (db-cAMP), resulted in a marked up-regulation of NOS expression by cardiomyocytes. In db-cAMP-stimulated cells, inhibition of protein kinase A (PKA) and protein kinase C (PKC) reduced immunolabeling of NOS and concomitantly lowered NO production. Taken together, these data point to an involvement of beta-adrenergic mechanisms, cytokine and PGI(2) receptors, adenylyl cyclase, PKA, and PKC in the control of NO generation and expression of NOS in rat cardiomyocytes.
authors.affiliation: Institute for Heart Research, Slovak Academy of Sciences, Bratislava, Slovak Republic.
authors.forename: Jan
authors.initials: J
authors.lastname: Slezak
authors.forename: Igor B
authors.initials: IB
authors.lastname: Buchwalow
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Schulze
authors.forename: Peter
authors.initials: P
authors.lastname: Karczewski
authors.forename: Gerd
authors.initials: G
authors.lastname: Wallukat
authors.forename: Vera E
authors.initials: VE
authors.lastname: Samoilova
authors.forename: Ernst-Georg
authors.initials: EG
authors.lastname: Krause
authors.forename: Joachim
authors.initials: J
authors.lastname: Neumann
authors.forename: Hermann
authors.initials: H
authors.lastname: Haller
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D003994:Bucladesine / Q000494:pharmacology; D002478:Cells, Cultured; D015971:Gene Expression Regulation, Enzymologic; D007527:Isoenzymes / Q000235:genetics / Q000378:metabolism*; D032383:Myocytes, Cardiac / Q000166:cytology / Q000187:drug effects / Q000201:enzymology* / Q000502:physiology; D009569:Nitric Oxide / Q000378:metabolism; D019001:Nitric Oxide Synthase / Q000235:genetics / Q000378:metabolism*; D009573:Nitrites / Q000378:metabolism; D047428:Protein Kinase Inhibitors / Q000378:metabolism; D051381:Rats; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology
chemical_list: D007527:Isoenzymes; D009573:Nitrites; D047428:Protein Kinase Inhibitors; D009569:Nitric Oxide; D003994:Bucladesine; D019001:Nitric Oxide Synthase; D013755:Tetradecanoylphorbol Acetate