Resveratrol Attenuates the Na+-Dependent Intracellular Ca2+ Overload by Inhibiting H2O2-Induced Increase in Late Sodium Current in Ventricular Myocytes

Chunping Qian,Peihua Zhang,Chao Wang,Ying Wu,Xiaojing Wang,Jihua Ma,Linghao Kong,Antao Luo,Shuo Zhang,Zhiqiang Ren,Zhong-Ping Feng

doi:10.1371/journal.pone.0051358

Abstract

Background/AimsResveratrol has been demonstrated to be protective in the cardiovascular system. The aim of this study was to assess the effects of resveratrol on hydrogen peroxide (H2O2)-induced increase in late sodium current (I Na.L) which augmented the reverse Na+-Ca2+ exchanger current (I NCX), and the diastolic intracellular Ca2+ concentration in ventricular myocytes.Methods I Na.L, I NCX, L-type Ca2+ current (I Ca.L) and intracellular Ca2+ properties were determined using whole-cell patch-clamp techniques and dual-excitation fluorescence photomultiplier system (IonOptix), respectively, in rabbit ventricular myocytes.ResultsResveratrol (10, 20, 40 and 80 µM) decreased I Na.L in myocytes both in the absence and presence of H2O2 (300 µM) in a concentration dependent manner. Ranolazine (3–9 µM) and tetrodotoxin (TTX, 4 µM), I Na.L inhibitors, decreased I Na.L in cardiomyocytes in the presence of 300 µM H2O2. H2O2 (300 µM) increased the reverse I NCX and this increase was significantly attenuated by either 20 µM resveratrol or 4 µM ranolazine or 4 µM TTX. In addition, 10 µM resveratrol and 2 µM TTX significantly depressed the increase by 150 µM H2O2 of the diastolic intracellular Ca2+ fura-2 fluorescence intensity (FFI), fura-fluorescence intensity change (△FFI), maximal velocity of intracellular Ca2+ transient rise and decay. As expected, 2 µM TTX had no effect on I Ca.L.ConclusionResveratrol protects the cardiomyocytes by inhibiting the H2O2-induced augmentation of I Na.L.and may contribute to the reduction of ischemia-induced lethal arrhythmias.

Highlights

Despite intensive research has been conducted in recent years, cardiac arrhythmias remain a serious problem
It has been reported that hypoxia increased INa.L in rat ventricular myocytes [4], and the increase in Na+ inflow during hypoxia increased [Na+]i which in turn rose the intracellular Ca2+ concentration ([Ca2+]i) via the Na+-Ca2+ exchanger (NCX) resulting in a Na+dependent intracellular Ca2+ overload induced by INa.L [5,6,7]
When INa.L was recorded under normal condition using depolarizing pulses with a duration of 300 ms applied at 0.25 Hz from a holding potential (HP) of 2120 mV in 10 mV increments between 270 and 220 mV, administration of 10, 20, 40 and 80 mM resveratrol resulted in decreased amplitudes of INa.L

Summary

Introduction

Despite intensive research has been conducted in recent years, cardiac arrhythmias remain a serious problem. Late sodium current (INa.L) has been recognized as an important factor contributing to the abnormal repolarization in ischemic and failured hearts [1]. INa.L plays an important role in determining the action potential duration (APD) [2] and the alteration of the intracellular Na+ concentration ([Na+]i) [3,4]. An increase in [Ca2+]i caused cardiac arrhythmias and irreversible cell damage [8]. Increased INa.L caused arrhythmic activity and contractile dysfunction [9,10]. Inhibition of INa.L is considered to be a new potential target for therapeutic intervention in patients with myocardial ischaemia and heart failure [10,11,12,13,14]

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