Zacopride Exerts an Antiarrhythmic Effect by Specifically Stimulating the Cardiac Inward Rectifier Potassium Current in Rabbits: Exploration of a New Antiarrhythmic Strategy

Author(s): Yuanyuan Lin, Junhu Li, Baozhong Zhu, Qinghua Liu, Xiaojie Bai, Bingmei Chang, Yanlin Guo, Qilong Feng*, Xuewen Li*, Bowei Wu, Jimin Cao

Journal Name: Current Pharmaceutical Design

Volume 26 , Issue 44 , 2020

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Background: Zacopride, a potent antagonist of 5-HT3 receptors and an agonist of 5-HT4 receptors, is a gastrointestinal prokinetic agent. In a previous study, we discovered that zacopride selectively stimulated the inward rectifier potassium current (IK1) in the rat and that agonizing IK1 prevented or eliminated aconitine-induced arrhythmias in rats.

Objective: Our aims were to confirm that the antiarrhythmic effects of zacopride are mediated by selectively enhancing IK1 in rabbits.

Methods: The effects of zacopride on the function of the main ion channels were investigated using a whole-cell patch-clamp technique in rabbits. Effects of zacopride on cardiac arrhythmias were also explored experimentally both in vivo and in vitro.

Results: Zacopride moderately enhanced cardiac IK1 but had no apparent action on voltage-gated sodium current (INa), L- type calcium current (ICa-L), sodium-calcium exchange current (INa/Ca), transient outward potassium current (Ito), or delayed rectifier potassium current (IK) in rabbits. Zacopride also had a marked antiarrhythmic effect in vivo and in vitro. We proved that the resting membrane potential (RMP) was hyperpolarized in the presence of 1 μmol/L zacopride, and the action potential duration (APD) at 90% repolarization (APD90) was shortened by zacopride (0.1-10 μmol/L) in a concentration- dependent manner. Furthermore, zacopride at 1 μmol/L significantly decreased the incidence of drug-induced early afterdepolarization (EAD) in rabbit ventricular myocytes.

Conclusion: Zacopride is a selective agonist of rabbit cardiac IK1 and that IK1 enhancement exerts potential antiarrhythmic effects.

Keywords: Zacopride, inward rectifier potassium current, rabbits, cardiomyocyte, arrhythmias, whole-cell patch-clamp, hyperpolarized.

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Article Details

Year: 2020
Published on: 01 July, 2020
Page: [5746 - 5754]
Pages: 9
DOI: 10.2174/1381612826666200701135508
Price: $65

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