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Updated: Aug 7, 2026
Analysis of Cardiac Contractile Dysfunction and Ca2+ Transients in Rodent Myocytes
Published on: May 25, 2022
Formation of reactive oxygen species at increased contraction frequency in rat cardiomyocytes
Frank R Heinzel1, Yukun Luo, Giuliano Dodoni
1Institut für Pathophysiologie, Universitätsklinikum Essen, Hufelandstrasse 55, 45122 Essen, Germany.
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 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.
Results:
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).
Conclusion:
Increased contraction frequency induces ROS formation in rat cardiomyocytes.
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