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Aim:To examine the effects of ginseng saponins on the heterologously expressedhuman ether-a-go-go related gene(HERG)that encodes the rapid component ofthe delayed rectifier K~+ channel.Methods:A two-electrode voltage clamp tech-nique was used.HERG currents were recorded in Xenopus oocytes injected withHERG cRNA.Results:Crude saponins of Korean red ginseng(GS)induced aminimal 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 orderof 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,GSincreased the outward HERG current.Conclusion:Ginseng saponins enhanceHERG currents,which could be in part a possible mechanism of the shorteningcardiac action potential of ginseng saponins.
Aim:To examine the effects of ginseng saponins on the heterologously expressedhuman 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 withHERG 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, declined 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 orderof 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 the a cardiac action potential, GSincreased the outward HERG current.Conclusion: Ginseng saponins enhanceHERG currents,which c Ould be in part a possible mechanism of the shorteningcardiac action potential of ginseng saponins.