Korean Circ J.
2003 Dec;33(12):1140-1146. 10.4070/kcj.2003.33.12.1140.
Effects of Oxygen Free Radicals on KATP Channel Activity in Mouse Cardiac Myocytes
- Affiliations
-
- 1Division of Cardiology, The Heart Center of Chonnam University Hospital, Korea.
- 2Department of Pharmacology, Chonnam National University, Gwangju, Korea.
- 3Chonnam National University Medical School and The Research Institute of Medical Sciences, Chonnam National University, Gwangju, Korea.
- KMID: 2227245
- DOI: http://doi.org/10.4070/kcj.2003.33.12.1140
Abstract
- BACKGROUND AND OBJECTIVE
Oxygen-derived free radicals (OFRs), produced as myocardium is reperfused after ischemic injury, contribute to reversible and irreversible cellular injury. KATP channels, activated by ischemia, have been reported to participate in the arrhythmogenic response to acute myocardial ischemia. Therefore, we examined the effects of OFRs on the regulation of KATP channel activity.
MATERIALS AND METHODS
Isolated mice (ICR) hearts were perfused with Tyrode's solution on a Langendorff apparatus. Single ventricular myocytes were isolated using enzymatic digestion with collagenase and protease. Single channel currents in the inside-out patch mode were recorded. OFRs were applied by mixing hypoxanthine and xanthine oxidase. The currents were recorded in the patch membrane at a holding potential of -60 mV.
RESULTS
OFRs generated by 0.1 U/mL xanthine oxidase and 0.5 mM hypoxanthine had no effects on the activities of KATP channels before and after treatment with 200 micrometer ATP. OFRs generated with 0.2 U/mL xanthine oxidase and 1.0 mM hypoxanthine reactivated the channel activities which had been attenuated by 100 micrometer ATP. In the presence of 100 U/mL superoxide dismutase and 122 U/mL catalase, which are OFRs scavengers, OFRs did not affect the KATP channels activities.
CONCLUSION
OFRs generated by the reaction of hypoxanthine and xanthine oxidase increased the KATP channel activities in the inside-out patch.
MeSH Terms
-
Adenosine Triphosphate
Animals
Catalase
Collagenases
Digestion
Free Radicals*
Heart
Hypoxanthine
Ischemia
KATP Channels
Membranes
Mice*
Muscle Cells
Myocardial Ischemia
Myocardium
Myocytes, Cardiac*
Oxygen*
Superoxide Dismutase
Xanthine Oxidase
Adenosine Triphosphate
Catalase
Collagenases
Free Radicals
Hypoxanthine
KATP Channels
Oxygen
Superoxide Dismutase
Xanthine Oxidase
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