title: Puerarin: a novel antagonist to inward rectifier potassium channel (IK1).
abstract: Puerarin, isolated from the root of pueraria, had been widely used to prevent and treat arrhythmia. We show that puerarin effectively prevents and reverses aconitine-induced arrhythmias in perfused heart in vitro and in rats in vivo. To study the mechanisms of antiarrhythmic action of puerarin, we investigated the electrophysiological actions of puerarin using whole-cell clamp in isolated rodent ventricular myocytes and two electrode voltage-clamp (TEV) in I(K1)-expressing Xenopus oocytes. Puerarin had no prominent effect on action potentials of ventricular myocytes from guinea pig. However, puerarin (1.2 mM) significantly inhibited the I(K1) current in rat ventricular cells. Consistently, puerarin blocked I(K1) expressed in Xenopus oocytes in a dose-dependent manner. Puerarin competed with barium, an open-channel blocker of I(K1), to inhibit I(K1) currents. Thus, our data demonstrated that puerarin is a novel open-channel blocker of I(K1), which may underlie the antiarrhythmic action of puerarin.
authors.affiliation: Department of Cardiology, Shaanxi Provincial Corps Hospital of Chinese People's Armed Police Forces, Xi'an, People's Republic of China. zl1017@126.com
authors.forename: Hua
authors.initials: H
authors.lastname: Zhang
authors.forename: Li
authors.initials: L
authors.lastname: Zhang
authors.forename: Qing
authors.initials: Q
authors.lastname: Zhang
authors.forename: XingCang
authors.initials: X
authors.lastname: Yang
authors.forename: JiYun
authors.initials: J
authors.lastname: Yu
authors.forename: ShuHong
authors.initials: S
authors.lastname: Shun
authors.forename: Yang
authors.initials: Y
authors.lastname: Wu
authors.forename: QianHui
authors.initials: Q
authors.lastname: Zeng
authors.forename: TingZhong
authors.initials: T
authors.lastname: Wang
mesh_terms: D000818:Animals; D000889:Anti-Arrhythmia Agents / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D006168:Guinea Pigs; D006352:Heart Ventricles / Q000187:drug effects; D007529:Isoflavones / Q000494:pharmacology*; D018408:Patch-Clamp Techniques; D024661:Potassium Channels, Inwardly Rectifying / Q000037:antagonists & inhibitors*; D051381:Rats; D017207:Rats, Sprague-Dawley; D014981:Xenopus
chemical_list: D000889:Anti-Arrhythmia Agents; D007529:Isoflavones; D024661:Potassium Channels, Inwardly Rectifying; C033607:puerarin