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Abnormal electrical activity induced by free radical generating systems in isolated cardiocytes
P L Barrington1, C F Meier, W B Weglicki
1Cardiovascular Research Program, Oklahoma Medical Research Foundation, Oklahoma City.
Journal of Molecular and Cellular Cardiology
|December 1, 1988
Summary
Oxygen free radicals can alter cardiac electrical function, leading to arrhythmias. This study shows free radicals induce changes in cardiocyte action potentials, mimicking clinical cardiac rhythm disturbances.
Area of Science:
- Cardiology
- Electrophysiology
- Oxidative Stress
Background:
- Pathological cardiac conditions are linked to arrhythmias.
- The direct impact of free radicals on myocardial electrical function remains unclear.
Purpose of the Study:
- To investigate the electrophysiological effects of free radicals on isolated adult canine ventricular cells.
- To determine if free radical generation can alter cardiac action potentials.
Main Methods:
- Superfusion of isolated canine ventricular cells with dihydroxyfumaric acid (DHF) to generate free radicals.
- Monitoring transmembrane action potentials using microelectrode techniques.
- Utilizing xanthine/xanthine oxidase system and antioxidant enzymes (superoxide dismutase, catalase) for further investigation.
Main Results:
- DHF superfusion induced progressive changes in action potentials, including altered plateau voltage and duration.
- Early and delayed afterdepolarizations, and triggered beats were observed.
- Cells eventually lost excitability due to severe depolarization and plateau collapse, mimicking arrhythmogenic conditions.
Conclusions:
- Free radicals can directly alter the electrophysiological properties of cardiomyocytes.
- These alterations in action potential characteristics resemble those underlying clinical cardiac arrhythmias.
- Antioxidant enzymes can mitigate the observed electrophysiological changes.