Issue Archive

Inhibitory effect of rhynchophylline on {sl human ether--a--go--go} related gene channel

Gui Le, Li Zhiwang, Du Rong, Yuan Guohui, Li Wei, Ren Faxin, Li Jing, Yang Junguo

Department of Cardiology, Affiliated Hospital, Nantong University.Nantong 226000,Jiangsu；China；Institute of Cardiovascular Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology.Wuhan 430030,Hubei

Abstract

We studied the effects of Chinese traditional medicine rhynchophylline (Rhy) on human ether-a-go-go related gene (HERG) channel and characterized the electrophysiological properties of Rhy's pharmacological effect on HERG channel using Xenopus oocytes. Xenopus oocytes were injected with either 23 nl (5.75 ng) HERG cRNA or 23 nl distilled water. Xenopus oocytes were randomly assigned to receive one of the following different concentrations of Rhy: (1) control, (2)10 #mu#mol/L Rhy, (3)100 #mu#mol/L Rhy, (4) 500 #mu#mol/L Rhy, (5) 1 000 #mu#mol/L Rhy, (6) 10 000 #mu#mol/L Rhy. Cell currents were recorded in oocytes. The peak tail currents of HERG channel were inhibited by Rhy. The inhibition was in a dose-dependent manner [IC_(50)=(773.4±42.5) #mu#mol/L]. Experiment with 100 #mu#mol/L Rhy indicated that the degree of HERG blockade showed some voltage dependence (within -40 mV to -20 mV ). Kinetic analyses revealed that Rhy decreased the rate of channel activation. The findings indicate that Rhy inhibits HERG encoded potassium channels. It may underline the molecular mechanism of myocardial electrophysiological characteristics associated with this drug.

Key words: HERG;rhynchophylline;oocyte;two-microelectrode voltage clamp

Received: 　　Accepted:

Corresponding author: 　　E-mail:

Citing This Article：

Gui Le, Li Zhiwang, Du Rong, Yuan Guohui, Li Wei, Ren Faxin, Li Jing, Yang Junguo. Inhibitory effect of rhynchophylline on {sl human ether--a--go--go} related gene channel. Acta Physiol Sin 2005; 57 (5): (in Chinese with English abstract).