Referenced in: none

Automatically associated channels: Kv1.5 , Slo1

Title: Torilin from Torilis japonica (Houtt.) DC. blocks hKv1.5 channel current.

Authors: Yong Geun Kwak, Dae Keun Kim, Tian-Ze Ma, Sun-Ah Park, Hoon Park, Young Hoon Jung, Dong-Jin Yoo, Jae Soon Eun

Journal, date & volume: Arch. Pharm. Res., 2006 Oct , 29, 834-9

PubMed link: http://www.ncbi.nlm.nih.gov/pubmed/17121176

Abstract
Torilin was purified from Torilis japonica (Houtt.) DC., and its effects on a rapidly activating delayed rectifier K+ channel (hKv1.5), cloned from human heart and stably expressed in Ltk- cells, as well as the corresponding K+ current (the ultrarapid delayed rectifier, I(KUR)) were assessed in human atrial myocytes. Using the whole cell configuration of the patch-clamp technique, torilin was found to inhibit the hKv1.5 current in time and voltage-dependent manners, with an IC50 value of 2.51+/-0.34 microM at +60 mV. Torilin accelerated the inactivation kinetics of the hKv1.5 channel, and slowed the deactivation kinetics of the hKv1.5 current, resulting in a tail crossover phenomenon. Additionally, torilin inhibited the hKv1.5 current in a use-dependent manner. These results strongly suggest that torilin is a type of open-channel blocker of the hKv1.5 channel.