title: Propranolol inhibits the human ether-a-go-go-related gene potassium channels.
abstract: Propranolol is a noncardioselective beta-adrenergic antagonist that has been recently reported to prolong the QTc interval on the surface electrocardiogram in humans when overdosed [Farhangi, V., Sansone, R.A. (2003). QTc prolongation due to propranolol overdose. Int. J. Psychiatry Med. 33, 201-202.]. To examine the underlying mechanisms for these clinical findings, we studied the effects of propranolol on the human cardiac potassium channels encoded by the ether-a-go-go-related gene (ERG) using the whole cell voltage-clamp technique. We found that propranolol blocked hERG currents in a concentration-dependent manner with an IC50 of 9.9+/-1.3 microM which is relevant to the predicted plasma level of propranolol in this case report. The present study demonstrated that propranolol can inhibit hERG channels. The interaction between propranolol and hERG channels could lead to delayed cardiac repolarization and might be a molecular mechanism for the previously reported QTc prolongation when propranolol is overdosed.
authors.affiliation: Department of Biochemical and Analytical Pharmacology, Research and Development, GlaxoSmithKline, NC 27709, USA. xiaozhou.x.yao@gsk.com
authors.forename: Xiaozhou
authors.initials: X
authors.lastname: Yao
authors.forename: Maggie S
authors.initials: MS
authors.lastname: McIntyre
authors.forename: Daniel G
authors.initials: DG
authors.lastname: Lang
authors.forename: Ivy H
authors.initials: IH
authors.lastname: Song
authors.forename: James D
authors.initials: JD
authors.lastname: Becherer
authors.forename: Mir A
authors.initials: MA
authors.lastname: Hashim
mesh_terms: D000319:Adrenergic beta-Antagonists / Q000494:pharmacology; D000818:Animals; D016466:CHO Cells; D006224:Cricetinae; D003412:Cricetulus; D004305:Dose-Response Relationship, Drug; D000072237:ERG1 Potassium Channel; D051638:Ether-A-Go-Go Potassium Channels; D006801:Humans; D008564:Membrane Potentials / Q000187:drug effects; D018408:Patch-Clamp Techniques; D024642:Potassium Channels, Voltage-Gated / Q000235:genetics / Q000502:physiology*; D011433:Propranolol / Q000494:pharmacology*
chemical_list: D000319:Adrenergic beta-Antagonists; D000072237:ERG1 Potassium Channel; D051638:Ether-A-Go-Go Potassium Channels; C000606913:KCNH2 protein, human; D024642:Potassium Channels, Voltage-Gated; D011433:Propranolol