Formation of reactive oxygen species at increased contraction frequency in rat cardiomyocytes

Reactive oxygen species (ROS) play an ambivalent role in cardiomyocytes: low concentrations are involved in cellular signaling, while higher concentrations contribute to cellular injury. We studied ROS formation during increases in contraction frequency in isolated cardiomyocytes. Rat ventricular ca...

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Bibliographic Details
Published in:Cardiovascular research 2006-07, Vol.71 (2), p.374-382
Main Authors: Heinzel, Frank R, Luo, Yukun, Dodoni, Giuliano, Boengler, Kerstin, Petrat, Frank, Di Lisa, Fabio, de Groot, Herbert, Schulz, Rainer, Heusch, Gerd
Format: Article
Language:English
Subjects:
Acetylcysteine - pharmacology
Animals
Antioxidants - pharmacology
Cells, Cultured
Diacetyl - analogs & derivatives
Diacetyl - pharmacology
Electric Stimulation
Enzyme Inhibitors - pharmacology
Microscopy, Fluorescence
Mitochondria, Heart - metabolism
Myocardial Contraction - physiology
Myocytes, Cardiac - metabolism
Myosins - antagonists & inhibitors
Myosins - metabolism
NADPH Oxidases - metabolism
NG-Nitroarginine Methyl Ester - pharmacology
Nitric Oxide Synthase - antagonists & inhibitors
Oxidation-Reduction
Oxygen Consumption
Rats
Rats, Sprague-Dawley
Reactive Oxygen Species - metabolism
Superoxides - metabolism
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Summary:Reactive oxygen species (ROS) play an ambivalent role in cardiomyocytes: low concentrations are involved in cellular signaling, while higher concentrations contribute to cellular injury. We studied ROS formation during increases in contraction frequency in isolated cardiomyocytes. Rat ventricular cardiomyocytes were loaded with dichlorodihydrofluorescein and electrically stimulated (37 degrees C). ROS formation was assessed by the rate of oxidation-dependent fluorescence increase (OxR). Oxygen consumption (VO(2)) and NAD(P)H autofluorescence were measured in parallel experiments. Increases in contraction frequency were accompanied by an increase in VO(2) and a decrease in NAD(P)H fluorescence. OxR increased to 124+/-4%, 146+/-8%, 204+/-25% and 256+/-29% of OxR at baseline during 1, 2, 3 and 4 Hz stimulation, and subsequently returned to baseline values with 0.2 Hz. The OxR increase was dose-dependently inhibited by the antioxidant NAC (10 and 100 mM), but unaffected by the NO synthase inhibitor l-NAME (200 microM and 10 mM). The OxR increase was attenuated when myosin ATPase activity was inhibited by butanedione monoxime (BDM; 5 mM). Increased contraction frequency induces ROS formation in rat cardiomyocytes.
ISSN:0008-6363
DOI:10.1016/j.cardiores.2006.05.014