中华医学杂志（英文版）2005，Vol.118Issue(14)：1161-1166,6.
Changes of IK,ATP current density and allosteric modulation during chronic atrial fibrillation
Changes of IK,ATP current density and allosteric modulation during chronic atrial fibrillation
WU Gang 1HUANG Cong-xin 1TANG Yan-hong 1JIANG Hong 1WAN Jun 1CHEN Hui 1XIE Qiang 1HUANG Zheng-rong1
作者信息
- 1. Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan 430060, China
- 折叠
摘要
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 μmol/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.关键词
atrial fibrillation/potassium current/current density/allosteric modulationKey words
atrial fibrillation/potassium current/current density/allosteric modulation分类
医药卫生引用本文复制引用
WU Gang,HUANG Cong-xin,TANG Yan-hong,JIANG Hong,WAN Jun,CHEN Hui ,XIE Qiang ,HUANG Zheng-rong..Changes of IK,ATP current density and allosteric modulation during chronic atrial fibrillation[J].中华医学杂志（英文版）,2005,118(14):1161-1166,6.
