Effects of Oxygen Free Radicals on KATP Channel Activity in Mouse Cardiac Myocytes

Hyung Wook Park, Jeong Min Ju, Ok Young Park, Woo Seok Park, Joo Han Kim, Weon Kim, Young Keun Ahn, Myung Ho Jeong, Jong Chun Park, Jae Ha Kim, Jung Chaee Kang, Jeong Gwan Cho
2003 Korean Circulation Journal  
and Objective:Oxygen-derived free radicals (OFRs), produced as myocardium is reperfused after ischemic injury, contribute to reversible and irreversible cellular injury. K ATP 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 K ATP channel activity. Materials and Methods: Isolated mice (ICR) hearts were perfused with Tyrode's solution on a Langendorff
more » ... n 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 K ATP channels before and after treatment with 200 μM 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 μM ATP. In the presence of 100 U/mL superoxide dismutase and 122 U/mL catalase, which are OFRs scavengers, OFRs did not affect the K ATP channels activities. Conclusion:OFRs generated by the reaction of hypoxanthine and xanthine oxidase increased the K ATP channel activities in the inside-out patch. (Korean Circulation J 2003 ; 33 (12) : 1140-1146 KEY WORDS:Oxygen free radicals;ATP-sensinve potassium channel. 서 론 우리나라에서 관상동맥질환은 최근 20여년 동안에 급 격히 증가하여 비외상성 사망의 가장 흔한 원인 질환의 하나가 되었다. 관상동맥질환은 임상적으로 협심증, 심근 경색증, 돌연사, 허혈성 심근증 등으로 표현되며 관상동 논문접수일:2003년 6월 18일 심사완료일:2003년 8월 29일 교신저자:조정관, 501-757 광주광역시 동구 학1동 8번지 전남대학교병원 순환기내과 전화:(062) 220-6242·전송:(062) 228-7274·E-mail:chojg@unitel.co.kr
doi:10.4070/kcj.2003.33.12.1140 fatcat:e2mibr3swbh5vkvjtce5vumnwa