首页 | 本学科首页   官方微博 | 高级检索  
检索        


Changes of IK,ATP current density and allosteric modulation during chronic atrial fibrillation
Authors:Wu Gang  Huang Cong-xin  Tang Yan-hong  Jiang Hong  Wan Jun  Chen Hui  Xie Qiang  Huang Zheng-rong
Institution:Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan 430060, China
Abstract:BACKGROUND: Atrial fibrillation (AF) is the most common supraventricular arrhythmia in clinical practice. Chronic atrial fibrillation (CAF) is associated with ionic remodeling. However, little is known about the activity of ATP-sensitive potassium current (IK, ATP) during CAF. So we studied the changes of IK, ATP density and allosteric modulation of ATP-sensitivity by intracellular pH during CAF. METHODS: Myocardium samples were obtained from the right auricular appendage of patients with rheumatic heart disease complicated with valvular disease in sinus rhythm (SR) or CAF. There were 14 patients in SR group and 9 patients in CAF group. Single atrial cells were isolated using an enzyme dispersion technique. IK, ATP was recorded using the whole-cell and inside-out configuration of voltage-clamp techniques. In whole-cell model, myocytes of SR and CAF groups were perfused with simulated ischemic solution to elicit IK, ATP. In inside-out configuration, the internal patch membranes were exposed to different ATP concentrations in pH 7.4 and 6.8. RESULTS: Under simulated ischemia, IK, ATP current density of CAF group was significantly higher than in SR group (83.5 +/- 10.8) vs. (58.7 +/- 8.4) pA/pF, P < 0.01]. IK, ATP of the two groups showed ATP concentration-dependent inhibition. The ATP concentration for 50% current inhibition (IC50) for the SR group was significantly different in pH 7.4 and pH 6.8 (24 vs. 74 micromol/L, P < 0.01). The IC50 did not change significantly in CAF group when the pH decreased from 7.4 to 6.8. CONCLUSIONS: During CAF, IK, ATP current density was increased and its allosteric modulation of ATP-sensitivity by intracellular pH was diminished.
Keywords:atrial fibrillation  potassium current  current density  allosteric modulation
本文献已被 CNKI 万方数据 PubMed 等数据库收录!
点击此处可从《中华医学杂志(英文版)》浏览原始摘要信息
点击此处可从《中华医学杂志(英文版)》下载免费的PDF全文
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号