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- Title
Formation of reactive oxygen species at increased contraction frequency in rat cardiomyocytes
- Authors
Heinzel, Frank R.; Luo, Yukun; Dodoni, Giuliano; Boengler, Kerstin; Petrat, Frank; Di Lisa, Fabio; de Groot, Herbert; Schulz, Rainer; Heusch, Gerd
- Abstract
Abstract: Objective: 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. Methods: Rat ventricular cardiomyocytes were loaded with dichlorodihydrofluorescein and electrically stimulated (37 °C). ROS formation was assessed by the rate of oxidation-dependent fluorescence increase (OxR). Oxygen consumption (V̇O2) and NAD(P)H autofluorescence were measured in parallel experiments. Results: Increases in contraction frequency were accompanied by an increase in V̇O2 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 μM and 10 mM). The OxR increase was attenuated when myosin ATPase activity was inhibited by butanedione monoxime (BDM; 5 mM). Conclusion: Increased contraction frequency induces ROS formation in rat cardiomyocytes.
- Subjects
REACTIVE oxygen species; HEART cells; MUSCLE cells; CARDIAC contraction
- Publication
Cardiovascular Research, 2006, Vol 71, Issue 2, p374
- ISSN
0008-6363
- Publication type
Article
- DOI
10.1016/j.cardiores.2006.05.014