RT Journal Article SR Electronic T1 Ginsenoside Rg3, a Gating Modifier of EAG Family K+ Channels JF Molecular Pharmacology JO Mol Pharmacol FD American Society for Pharmacology and Experimental Therapeutics SP 469 OP 482 DO 10.1124/mol.116.104091 VO 90 IS 4 A1 Wei Wu A1 Alison Gardner A1 Frank B. Sachse A1 Michael C. Sanguinetti YR 2016 UL http://molpharm.aspetjournals.org/content/90/4/469.abstract AB Ginsenoside 20(S)-Rg3 (Rg3) is a steroid glycoside that induces human ether-à-go-go-related gene type 1 (hERG1, Kv11.1) channels to activate at more negative potentials and to deactivate more slowly than normal. However, it is unknown whether this action is unique to hERG1 channels. Here we compare and contrast the mechanisms of actions of Rg3 on hERG1 with three other members of the ether-à-go-go (EAG) K+ channel gene family, including EAG1 (Kv10.1), ERG3 (Kv11.3), and ELK1 (Kv12.1). All four channel types were heterologously expressed in Xenopus laevis oocytes, and K+ currents were measured using the two-microelectrode voltage-clamp technique. At a maximally effective concentration, Rg3 shifted the half-point of voltage-dependent activation of currents by −14 mV for ERG1 (EC50 = 414 nM), −20 mV for ERG3 (EC50 = 374 nM), −28 mV for EAG1 (EC50 = 1.18 μM), and more than −100 mV for ELK1 (EC50 = 197 nM) channels. Rg3 also induced slowing of ERG1, ERG3, and ELK1 channel deactivation and accelerated the rate of EAG1 channel activation. A Markov model was developed to simulate gating and the effects of Rg3 on the voltage dependence of activation of hELK1 channels. Understanding the mechanism underlying the action of Rg3 may facilitate the development of more potent and selective EAG family channel activators as therapies for cardiovascular and neural disorders.