Discrepant electrophysiological characteristics and calcium homeostasis of left atrial anterior and posterior myocytes

Kazuyoshi Suenari, Yao Chang Chen, Yu Hsun Kao, Chen Chuan Cheng, Yung Kuo Lin, Yi Jen Chen, Shih Ann Chen

研究成果: 雜誌貢獻文章

37 引文 斯高帕斯(Scopus)

摘要

The left atrial (LA) posterior wall has been demonstrated to have regional electrophysiological differences with a higher arrhythmogenic potential leading to atrial fibrillation (AF). However, the ionic characteristics and calcium regulation in the LA anterior and posterior myocytes have not been fully elucidated. The purpose of this study was to investigate the electrical characteristics of the LA anterior and posterior myocytes. Whole-cell patch-clamp techniques and the indo-1 fluorimetric ratio technique were used to investigate the characteristics of the ionic currents, action potentials, and intracellular calcium in single isolated rabbit myocytes in the LA anterior and posterior walls. The expression of the Na+-Ca2+ exchanger (NCX) and ryanodine receptor (RyR) were evaluated by a Western blot. The LA posterior myocytes (n = 15) had a higher incidence (53 vs. 19%, P <0.05) of delayed afterdepolarizations than the LA anterior myocytes (n = 16). The LA posterior myocytes had larger sodium currents and late sodium currents, but smaller inward rectifier potassium currents than the LA anterior myocytes. The LA posterior myocytes had larger intracellular Ca2+ transient and sarcoplasmic reticulum Ca2+ contents as compared with the LA anterior myocytes. However, the NCX currents in the LA posterior myocytes were smaller than those in the LA anterior myocytes. The LA posterior myocytes had a smaller protein expression of NCX, but a larger protein expression of RyR than the LA anterior myocytes. In conclusion, LA posterior myocytes contain a high arrhythmogenic potential and distinctive electrophysiological characteristics, which may contribute to the pathophysiology of AF.
原文英語
頁(從 - 到)65-74
頁數10
期刊Basic Research in Cardiology
106
發行號1
DOIs
出版狀態已發佈 - 一月 2011

ASJC Scopus subject areas

  • Cardiology and Cardiovascular Medicine
  • Physiology (medical)
  • Physiology

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