Effects of vesnarinone on nitric oxide synthesis in rat cardiac myocytes.
OBJECTIVE
The purpose of this study was to investigate the effects of vesnarinone on nitric oxide (NO) synthesis in cardiac myocytes.


METHODS
We measured the accumulation of nitrite, a stable oxidation product of NO synthase (iNOS) protein in cultured neonatal rat cardiac myocytes.


RESULTS
Incubation of the cultures with interleukin-1 beta (IL-1 beta; 10 ng/ml) and tumor necrosis factor alpha (TNF alpha; 10 ng/ml) caused a marked increase in nitrite production. Although vesnarinone by itself showed no effect on nitrite accumulation, it enhanced cytokine-induced nitrite production by cardiac myocytes in a dose-dependent manner. The effect of vesnarinone was completely abolished in the presence of NG-monomethyl-L-arginine or actinomycin D. The vesnarinone-induced nitrite production was accompanied by increased iNOS protein expression. In the presence of dibutyryl-cAMP, cytokine-induced nitrite accumulation was further increased, but the stimulatory effect on vesnarinone on nitrite accumulation was diminished. The effect of vesnarinone was also inhibited by Rp-8-Br-cAMPS, a competitive inhibitor of protein kinase A, in a dose-dependent manner.


CONCLUSIONS
These findings indicate that vesnarinone increases NO synthesis in cytokine-stimulated cardiac myocytes, at least partially through a cAMP-dependent pathway.
Department of Cardiology, Jichi Medical School, Tochigi, Japan.
K
K
Kurosaki
U
U
Ikeda
Y
Y
Maeda
M
M
Shimpo
S
S
Ueno
K
K
Shimada
D015124:8-Bromo Cyclic Adenosine Monophosphate / Q000031:analogs & derivatives / Q000494:pharmacology; D000704:Analysis of Variance; D000818:Animals; D000831:Animals, Newborn; D003994:Bucladesine / Q000494:pharmacology; D002316:Cardiotonic Agents / Q000494:pharmacology*; D002478:Cells, Cultured; D017077:Culture Media, Conditioned / Q000737:chemistry; D054746:Cyclic AMP-Dependent Protein Kinase Type II; D017868:Cyclic AMP-Dependent Protein Kinases / Q000037:antagonists & inhibitors; D003609:Dactinomycin / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D007375:Interleukin-1 / Q000494:pharmacology; D009206:Myocardium / Q000378:metabolism*; D009569:Nitric Oxide / Q000096:biosynthesis*; D019001:Nitric Oxide Synthase / Q000032:analysis / Q000037:antagonists & inhibitors; D052247:Nitric Oxide Synthase Type II; D009573:Nitrites / Q000032:analysis; D011500:Protein Synthesis Inhibitors / Q000494:pharmacology; D011719:Pyrazines; D011804:Quinolines / Q000494:pharmacology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D013873:Thionucleotides / Q000494:pharmacology; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology; D019323:omega-N-Methylarginine / Q000494:pharmacology
C105593:8-bromoadenosine-3',5'-cyclic monophosphorothioate; D002316:Cardiotonic Agents; D017077:Culture Media, Conditioned; D007375:Interleukin-1; D009573:Nitrites; D011500:Protein Synthesis Inhibitors; D011719:Pyrazines; D011804:Quinolines; D013873:Thionucleotides; D014409:Tumor Necrosis Factor-alpha; D003609:Dactinomycin; D015124:8-Bromo Cyclic Adenosine Monophosphate; D019323:omega-N-Methylarginine; D009569:Nitric Oxide; C041667:vesnarinone; D003994:Bucladesine; D019001:Nitric Oxide Synthase; D052247:Nitric Oxide Synthase Type II; C496318:Nos2 protein, rat; D054746:Cyclic AMP-Dependent Protein Kinase Type II; D017868:Cyclic AMP-Dependent Protein Kinases