Effects of Oxygen Free Radical on Action Potential in Mouse Atrial Myocardium.
10.4070/kcj.2006.36.2.108
- Author:
Hyung Wook PARK
1
;
Dae Ho JEONG
;
Nam Sik YOON
;
Jeom Suk KOH
;
Sang Yup LIM
;
Sang Rok LEE
;
Seo Na HONG
;
Kye Hun KIM
;
Il Suk 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
Author Information
1. Division of Cardiology, Chonnam University Hospital, Gwangju, Korea. chojg@unitel.co.kr
- Publication Type:Original Article
- Keywords:
Free radicals;
Action potentials;
Atrial fibrillation
- MeSH:
Action Potentials*;
Animals;
Atrial Fibrillation;
Atrial Remodeling;
Free Radicals;
Heart Arrest;
Hydrogen Peroxide;
Membrane Potentials;
Mice*;
Myocardium*;
Oxygen*;
Reactive Oxygen Species
- From:Korean Circulation Journal
2006;36(2):108-114
- CountryRepublic of Korea
- Language:Korean
-
Abstract:
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% O2, 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 (H2O2 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 APD50 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.
