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Block of HERG k channel by classic histamine h(1) receptor antagonist chlorpheniramine.

ABSTRACT: Chlorpheniramine is a potent first-generation histamine H(1) receptor antagonist that can increase action potential duration and induce QT prolongation in several animal models. Since block of cardiac human ether-a-go-go-related gene (hERG) channels is one of leading causes of acquired long QT syndrome, we investigated the acute effects of chlorpheniramine on hERG channels to determine the electrophysiological basis for its proarrhythmic potential. We examined the effects of chlorpheniramine on the hERG channels expressed in Xenopus oocytes using two-microelectrode voltage-clamp techniques. Chlorpheniramine induced a concentration-dependent decrease of the current amplitude at the end of the voltage steps and hERG tail currents. The IC(50) of chlorpheniramine-dependent hERG block in Xenopus oocytes decreased progressively relative to the degree of depolarization. Chlorpheniramine affected the channels in the activated and inactivated states but not in the closed states. The S6 domain mutations Y652A and F656A partially attenuated (Y652A) or abolished (F656A) the hERG current block. These results suggest that the H(1) antihistamine, chlorpheniramine is a blocker of the hERG channels, providing a molecular mechanism for the drug-induced arrhythmogenic side effects.

SUBMITTER: Hong HK

PROVIDER: S-EPMC2766741 | biostudies-literature | 2009 Jun

REPOSITORIES: biostudies-literature

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Block of HERG k channel by classic histamine h(1) receptor antagonist chlorpheniramine.

Hong Hee-Kyung HK Jo Su-Hyun SH

The Korean journal of physiology & pharmacology : official journal of the Korean Physiological Society and the Korean Society of Pharmacology 20090630 3

Chlorpheniramine is a potent first-generation histamine H(1) receptor antagonist that can increase action potential duration and induce QT prolongation in several animal models. Since block of cardiac human ether-a-go-go-related gene (hERG) channels is one of leading causes of acquired long QT syndrome, we investigated the acute effects of chlorpheniramine on hERG channels to determine the electrophysiological basis for its proarrhythmic potential. We examined the effects of chlorpheniramine on ...[more]

PMID: 19885040

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Dataset Information

Block of HERG k channel by classic histamine h(1) receptor antagonist chlorpheniramine.

Publications

Block of HERG k channel by classic histamine h(1) receptor antagonist chlorpheniramine.

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