Effects of oxygen free radical on action potential in mouse atrial myocardium

Hyung Wook Park, Dae Ho Jeong, Nam Sik Yoon, Jeom Suk Koh, Sang Yup Lim, Sang Rok Lee, Seo Na Hong, Kye Hun Kim, Suk Il Sohn, Young Joon Hong, Ju Han Kim, Weon Kim, Ryung Hwa Park, Jeong Min Ju, Young Keun Ahn, Myung Ho Jeong, Jeong Gwan Cho, Jae Ha Kim, Jong Chun Park, Jung Chaee Kang

Research output: Contribution to journalArticlepeer-review


Background and Objectives: Reactive oxygen species are known to be produced when atrial fibrillation develops. This study was performed to investigate the effects of hydrogen peroxide (H2O2) on the action potential parameters of the mouse atrium. Subjects and Methods: Mouse (ICR) atrial fibers were excised and immersed in cold bicarbonate-containing Tyrode's solution. The preparations were then perfused with oxygenated (95% O 2, 5% CO2) Tyrode's solution and driven by an electrical stimuli 1 ms in duration at a frequency of 1 Hz. The transmembrane potentials were recorded at 0, 2.5, 5, 10, 20 and 30 minute, and compared between groups I (control), II (H2O2 0.1 mM), III (H2O 2 0.5 mM) and IV (H2O2 1 mM). Results: In group I, the maximal diastolic potential (MDP), action potential amplitude (APA), maximal slope at phase 0 depolarization (Vmax), action potential duration until 50% and 90% of repolarization (APD50, APD90) were unchanged with increasing time. In group II, the MDP and APA were unchanged, but the Vmax was decreased, and the APD50 and APD90 prolonged. In group III, the MDP was increased and the Vmax decreased;! the APD50 and APD90 were prolonged, but the APA unchanged. In group IV, the MDP was increased, the Vmax and APA decreased And the APD 50 and APD90 prolonged. After-depolarization was observed in 40% (8/20) and 54.5% (12/22) of groups III and IV, respectively, and asystole occurred in 18.2% (4/22) of group IV. Conclusion: Hydrogen peroxide changed the action potential parameters in both time and dose dependent manner, and also elicited after-depolarization at higher concentrations. These results suggest reactive oxygen species are involved in the electrical remodeling and arrhythmogenesis in atrial myocardium.

Original languageEnglish
Pages (from-to)108-114
Number of pages7
JournalKorean Circulation Journal
Issue number2
Publication statusPublished - 2006 Feb
Externally publishedYes


  • Action potentials
  • Atrial fibrillation
  • Free radicals

ASJC Scopus subject areas

  • Internal Medicine
  • Cardiology and Cardiovascular Medicine


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