Modulating effect of ginseng saponins on heterologously expressed HERG currents in Xenopus oocytes  

作　　者：Cuk-seongKIM Sook-jinSON Hyo-shinKIM Yong-dukKIM Kyu-seungLEE Byeong-hwaJEON Kwang-jinKIM Jin-kyu PARK Jin-bong PARK 

机构地区：[1]Department of Physiology,College of Medicine,Chungnam National University,Daejeon 301-131,Korea [2]Korea Ginseng and Tobacco Research Institute,Daejeon 305-805,Korea

出　　处：《Acta Pharmacologica Sinica》2005年第5期551-558,共8页中国药理学报（英文版）

基　　金：Project supported by a grant from Korea Research Foundation(2000-002-E00005)

摘　　要：Aim:To examine the effects of ginseng saponins on the heterologously expressed human ether-a-go-go related gene(HERG)that encodes the rapid component of the delayed rectifier K^+ channel.Methods:A two-electrode voltage clamp tech- nique was used.HERG currents were recorded in Xenopus oocytes injected with HERG cRNA.Results:Crude saponins of Korean red ginseng(GS)induced a minimal increase of the maximal HERG conductance without changes in the volt- age-dependent HERG current activation and inactivation curves.GS,however, decelerated HERG current deactivation in a concentration-dependent manner, which was more noticeable with panaxitriol(PT)than panaxidiol(PD).Consistently, ginseng saponins increased the HERG deactivation time constants with the order of potency of Rg_1(a maj or component of PT)>Rf_1>Rb_1(a major component of PD). Re had little effect on HERG deactivation.During a cardiac action potential,GS increased the outward HERG current.Conclusion:Ginseng saponins enhance HERG currents,which could be in part a possible mechanism of the shortening cardiac action potential of ginseng saponins.Aim:To examine the effects of ginseng saponins on the heterologously expressed human ether-a-go-go related gene(HERG)that encodes the rapid component of the delayed rectifier K^+ channel.Methods:A two-electrode voltage clamp tech- nique was used.HERG currents were recorded in Xenopus oocytes injected with HERG cRNA.Results:Crude saponins of Korean red ginseng(GS)induced a minimal increase of the maximal HERG conductance without changes in the volt- age-dependent HERG current activation and inactivation curves.GS,however, decelerated HERG current deactivation in a concentration-dependent manner, which was more noticeable with panaxitriol(PT)than panaxidiol(PD).Consistently, ginseng saponins increased the HERG deactivation time constants with the order of potency of Rg_1(a maj or component of PT)>Rf_1>Rb_1(a major component of PD). Re had little effect on HERG deactivation.During a cardiac action potential,GS increased the outward HERG current.Conclusion:Ginseng saponins enhance HERG currents,which could be in part a possible mechanism of the shortening cardiac action potential of ginseng saponins.

关 键 词：Ginseng saponins Xenopus laevis potassium channels action potentials patch-clamp techniques 

分 类 号：R285[医药卫生—中药学]