부산대학교 도서관

Background Atrial fibrillation ( AF) is the most common sustained arrhythmia, and pulmonary veins ( PVs) play a critical role in triggering AF. Angiotensin (Ang)-(1-7) regulates calcium (Ca2+) homoeostasis and also plays a critical role in cardiovascular pathophysiology. However, the role of Ang-(1-7) in PV arrhythmogenesis remains unclear. Materials and methods Conventional microelectrodes, whole-cell patch-clamp and the fluo-3 fluorimetric ratio technique were used to record ionic currents and intracellular Ca2+ in isolated rabbit PV preparations and in single isolated PV cardiomyocytes, before and after administration of Ang-(1-7). Results Ang (1-7) concentration dependently (0.1, 1, 10 and 100 nmol/L) decreased PV spontaneous electrical activity. Ang-(1-7) (100 nmol/L) decreased the late sodium (Na+), L-type Ca2+ and Na+-Ca2+ exchanger currents, but did not affect the voltage-dependent Na+ current in PV cardiomyocytes. In addition, Ang-(1-7) decreased intracellular Ca2+ transient and sarcoplasmic reticulum Ca2+ content in PV cardiomyocytes. A779 (a Mas receptor blocker, 3 μmol/L), L- NAME (a NO synthesis inhibitor, 100 μmol/L) or wortmannin (a specific PI3K inhibitor, 10 nmol/L) attenuated the effects of Ang-(1-7) (100 nmol/L) on PV spontaneous electric activity. Conclusion Ang-(1-7) regulates PV electrophysiological characteristics and Ca2+ homoeostasis via Mas/ PI3K/ eNOS signalling pathway. [ABSTRACT FROM AUTHOR]