guanosine-diphosphate and 3-nitrotyrosine

Excess catecholamine levels are suggested to be cardiotoxic and to underlie stress-induced heart failure. The cardiotoxic effects of norepinephrine and epinephrine are well recognized. However, although cardiac and circulating dopamine levels are also increased in stress cardiomyopathy patients, knowledge regarding putative toxic effects of excess dopamine levels on cardiomyocytes is scarce. We now studied the effects of elevated dopamine levels in H9c2 cardiomyoblasts. H9c2 cells were cultured and treated with dopamine (200 μM) for 6, 24, and 48 h. Subsequently, the effects on lipid accumulation, cell viability, flippase activity, reactive oxygen species (ROS) production, subcellular NADPH oxidase (NOX) protein expression, and ATP/ADP and GTP/GDP levels were analyzed. Dopamine did not result in cytotoxic effects after 6 h. However, after 24 and 48 h dopamine treatment induced a significant increase in lipid accumulation, nitrotyrosine levels, indicative of ROS production, and cell death. In addition, dopamine significantly reduced flippase activity and ATP/GTP levels, coinciding with phosphatidylserine exposure on the outer plasma membrane. Furthermore, dopamine induced a transient increase in cytoplasmic and (peri)nucleus NOX1 and NOX4 expression after 24 h that subsided after 48 h. Moreover, while dopamine induced a similar transient increase in cytoplasmic NOX2 and p47

Topics: Adenosine Diphosphate; Adenosine Triphosphate; Animals; Caspase 3; Cell Line; Cell Membrane; Cell Survival; Dopamine; Dopamine Agents; Flow Cytometry; Guanosine Diphosphate; Guanosine Triphosphate; Hydrogen-Ion Concentration; Inflammation; Lipid Metabolism; Microscopy, Electron; Microscopy, Fluorescence; Myoblasts, Cardiac; NADH, NADPH Oxidoreductases; NADPH Oxidase 1; NADPH Oxidase 4; NADPH Oxidases; Nuclear Proteins; Oxidative Stress; Peroxidase; Rats; Reactive Oxygen Species; Soluble N-Ethylmaleimide-Sensitive Factor Attachment Proteins; Tyrosine