Referenced in: none

Automatically associated channels: Kv1.5 , Slo1

Title: Open channel block of hKv1.5 by psoralen from Heracleum moellendorffii Hance.

Authors: Jae Soon Eun, Bok Hee Choi, Jeong Ah Park, Ggot Im Lee, Taek Yul Lee, Dae Keun Kim, Young Hoon Jung, Dong Jin Yoo, Yong Geun Kwak

Journal, date & volume: Arch. Pharm. Res., 2005 Mar , 28, 269-73

PubMed link: http://www.ncbi.nlm.nih.gov/pubmed/15832811

Abstract
A furocoumarin derivative, psoralen (7H-furo[3,2-g][1]benzopyran-7-one), was isolated from the n-hexane fraction of Heracleum moellendorffii Hance. We examined the effects of psoralen on a human Kv1.5 potassium channel (hKv1.5) cloned from human heart and stably expressed in Ltk- cells. We found that psoralen inhibited the hKv1.5 current in a concentration-, use- and voltage-dependent manner with an IC50 value of 180 +/- 21 nM at +60 mV. Psoralen accelerated the inactivation kinetics of the hKv1.5 channel, and it slowed the deactivation kinetics of the hKv1.5 current resulting in a tail crossover phenomenon. These results indicate that psoralen acts on the hKv1.5 channel as an open channel blocker. Furthermore, psoralen prolonged the action potential duration of rat atrial muscles in a dose-dependent manner. Taken together, the present results strongly suggest that psoralen may be an ideal antiarrhythmic drug for atrial fibrillation.