Biomaterial Database

Inhibitory effects of the class III antiarrhythmic drug amiodarone on cloned HERG potassium channels. 1999

J Kiehn, and D Thomas, and C A Karle, and W Schöls, and W Kübler

Department of Cardiology, Medical Hospital, University of Heidelberg, Germany. johann kiehn@UKL.uni-heidelberg.de

The human ether-a-go-go-related gene (HERG) encodes a K+ channel with biophysical properties nearly identical to the rapid component of the cardiac-delayed rectifier K+ current (I(Kr)). HERG channels are one primary target for the pharmacological management of arrhythmias. In this study, we investigated the acute effects of the class III antiarrhythmic drug amiodarone on HERG channels expressed heterologously in Xenopus oocytes by use of the two-microelectrode voltage clamp technique. Amiodarone blocked HERG channels with an IC50 of 9.8 microM with a maximum outward tail current reduction of 62.8%. The block consisted of two main components, a closed channel block that could not be reversed within the time of experiments and an open channel block with a slow unblock, having a recovery time constant of 73 s at -80 mV. Inactivation of the HERG channel at very positive potentials could not prevent amiodarone block. These results indicate that HERG channels can be blocked by amiodarone in closed, open and inactivated states. The block of open channels was cumulative, use-dependent and voltage-dependent. In summary, our data suggest that the strong class III antiarrhythmic action of amiodarone is at least partially based upon its acute inhibitory effects on HERG potassium channels.

UI	MeSH Term	Description	Entries
D009865	Oocytes	Female germ cells derived from OOGONIA and termed OOCYTES when they enter MEIOSIS. The primary oocytes begin meiosis but are arrested at the diplotene state until OVULATION at PUBERTY to give rise to haploid secondary oocytes or ova (OVUM).	Ovocytes,Oocyte,Ovocyte
D003001	Cloning, Molecular	The insertion of recombinant DNA molecules from prokaryotic and/or eukaryotic sources into a replicating vehicle, such as a plasmid or virus vector, and the introduction of the resultant hybrid molecules into recipient cells without altering the viability of those cells.	Molecular Cloning
D004268	DNA-Binding Proteins	Proteins which bind to DNA. The family includes proteins which bind to both double- and single-stranded DNA and also includes specific DNA binding proteins in serum which can be used as markers for malignant diseases.	DNA Helix Destabilizing Proteins,DNA-Binding Protein,Single-Stranded DNA Binding Proteins,DNA Binding Protein,DNA Single-Stranded Binding Protein,SS DNA BP,Single-Stranded DNA-Binding Protein,Binding Protein, DNA,DNA Binding Proteins,DNA Single Stranded Binding Protein,DNA-Binding Protein, Single-Stranded,Protein, DNA-Binding,Single Stranded DNA Binding Protein,Single Stranded DNA Binding Proteins
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D000071230	Transcriptional Regulator ERG	A trans-activator and member of the erythroblast transformation-specific family of transcriptions factors that contain a characteristic ETS MOTIF. It is required for PLATELET CELL ADHESION to the subendothelium and associates with CHIMERIC ONCOGENE PROTEINS in PROSTATE CANCER; EWING'S SARCOMA; and ACUTE MYELOID LEUKEMIA.	Transforming Protein ERG,V-Ets Avian Erythroblastosis Virus E26 Oncogene Homolog Protein,V-Ets Avian Erythroblastosis Virus E26 Oncogene Related Protein,V Ets Avian Erythroblastosis Virus E26 Oncogene Homolog Protein,V Ets Avian Erythroblastosis Virus E26 Oncogene Related Protein
D000072237	ERG1 Potassium Channel	One of three members of the ether-a-go-go (EAG) POTASSIUM CHANNELS gene family comprising ether-a-go-go (eag), eag-like (elk) and eag-related (erg) subfamilies. Ether-a-go-go-related gene 1 (ERG1) also known as KCNH2, encodes the pore-forming subunit of a rapidly activating-delayed rectifier potassium channel that plays an essential role in the final repolarization of ventricular action potential. Loss-of-function mutations in human hERG1 is associated with life-threatening ARRHYTHMIA.	Ether-A-Go-Go-Related Potassium Channel 1,Kv11.1 Protein-Potassium Channel,Potassium Voltage-Gated Channel, Subfamily H, Member 2,Channel, ERG1 Potassium,Channel, Kv11.1 Protein-Potassium,Ether A Go Go Related Potassium Channel 1,Kv11.1 Protein Potassium Channel,Potassium Channel, ERG1,Protein-Potassium Channel, Kv11.1
D000638	Amiodarone	An antianginal and class III antiarrhythmic drug. It increases the duration of ventricular and atrial muscle action by inhibiting POTASSIUM CHANNELS and VOLTAGE-GATED SODIUM CHANNELS. There is a resulting decrease in heart rate and in vascular resistance.	Amiobeta,Amiodarex,Amiodarona,Amiodarone Hydrochloride,Amiohexal,Aratac,Braxan,Corbionax,Cordarex,Cordarone,Kordaron,L-3428,Ortacrone,Rytmarone,SKF 33134-A,Tachydaron,Trangorex,Hydrochloride, Amiodarone,L 3428,L3428,SKF 33134 A,SKF 33134A
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia
D000889	Anti-Arrhythmia Agents	Agents used for the treatment or prevention of cardiac arrhythmias. They may affect the polarization-repolarization phase of the action potential, its excitability or refractoriness, or impulse conduction or membrane responsiveness within cardiac fibers. Anti-arrhythmia agents are often classed into four main groups according to their mechanism of action: sodium channel blockade, beta-adrenergic blockade, repolarization prolongation, or calcium channel blockade.	Anti-Arrhythmia Agent,Anti-Arrhythmia Drug,Anti-Arrhythmic,Antiarrhythmia Agent,Antiarrhythmia Drug,Antiarrhythmic Drug,Antifibrillatory Agent,Antifibrillatory Agents,Cardiac Depressant,Cardiac Depressants,Myocardial Depressant,Myocardial Depressants,Anti-Arrhythmia Drugs,Anti-Arrhythmics,Antiarrhythmia Agents,Antiarrhythmia Drugs,Antiarrhythmic Drugs,Agent, Anti-Arrhythmia,Agent, Antiarrhythmia,Agent, Antifibrillatory,Agents, Anti-Arrhythmia,Agents, Antiarrhythmia,Agents, Antifibrillatory,Anti Arrhythmia Agent,Anti Arrhythmia Agents,Anti Arrhythmia Drug,Anti Arrhythmia Drugs,Anti Arrhythmic,Anti Arrhythmics,Depressant, Cardiac,Depressant, Myocardial,Depressants, Cardiac,Depressants, Myocardial,Drug, Anti-Arrhythmia,Drug, Antiarrhythmia,Drug, Antiarrhythmic,Drugs, Anti-Arrhythmia,Drugs, Antiarrhythmia,Drugs, Antiarrhythmic
D013997	Time Factors	Elements of limited time intervals, contributing to particular results or situations.	Time Series,Factor, Time,Time Factor