Document Detail


Interactions of the 5-hydroxytryptamine 3 antagonist class of antiemetic drugs with human cardiac ion channels.
MedLine Citation:
PMID:  11046096     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Administration of the 5-hydroxytryptamine 3 receptor class of antiemetic agents has been associated with prolongation in the QRS, JT, and QT intervals of the ECG. To explore the mechanisms underlying these findings, we examined the effects of granisetron, ondansetron, dolasetron, and the active metabolite of dolasetron MDL 74,156 on the cloned human cardiac Na(+) channel hH1 and the human cardiac K(+) channel HERG and the slow delayed rectifier K(+) channel KvLQT1/minK. Using patch-clamp electrophysiology we found that all of the drugs blocked Na(+) channels in a frequency-dependent manner. At a frequency of 3 Hz, the IC(50) values for block of Na(+) current measured 2.6, 88.5, 38.0, and 8.5 microM for granisetron, ondansetron, dolasetron, and MDL 74,156, respectively. Block was relieved by strong hyperpolarizing potentials, suggesting a possible interaction with an inactivated channel state. Recovery from inactivation was impaired at -80 mV compared with -100 mV, and the fractional recovery was impaired by drug in a concentration-dependent manner. IC(50) values for block of the HERG cardiac K(+) channel measured 3.73, 0.81, 5.95, and 12.1 microM for granisetron, ondansetron, dolasetron, and MDL 74,156, respectively. Ondansetron (3 microM) also slowed decay of HERG tail currents. In contrast, none of these drugs (10 microM) produced greater than 30% block of the slow delayed rectifier K(+) channel KvLQT1/minK. We concluded that the antiemetic agents tested in this study block human cardiac Na(+) channels probably by interacting with the inactivated state. This may lead to clinically relevant Na(+) channel blockade, especially when high heart rates or depolarized/ischemic tissue is present. The submicromolar affinity of ondansetron for the HERG K(+) channel likely underlies the prolongation of cardiac repolarization reported for this drug.
Authors:
Y A Kuryshev; A M Brown; L Wang; C R Benedict; D Rampe
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Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  The Journal of pharmacology and experimental therapeutics     Volume:  295     ISSN:  0022-3565     ISO Abbreviation:  J. Pharmacol. Exp. Ther.     Publication Date:  2000 Nov 
Date Detail:
Created Date:  2000-11-02     Completed Date:  2000-11-21     Revised Date:  2008-10-28    
Medline Journal Info:
Nlm Unique ID:  0376362     Medline TA:  J Pharmacol Exp Ther     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  614-20     Citation Subset:  IM    
Affiliation:
ChanTest, Inc., Cleveland, Ohio, USA.
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MeSH Terms
Descriptor/Qualifier:
Antiemetics / pharmacology*
Cation Transport Proteins*
Cell Line
Cloning, Molecular
DNA-Binding Proteins*
Dose-Response Relationship, Drug
Electric Stimulation
Ether-A-Go-Go Potassium Channels
Granisetron / pharmacology
Heart / drug effects*,  physiology
Humans
Indoles / pharmacology
KCNQ Potassium Channels
KCNQ1 Potassium Channel
Ondansetron / pharmacology
Potassium Channels / drug effects,  genetics,  physiology*
Potassium Channels, Voltage-Gated*
Quinolizines / pharmacology
Receptors, Serotonin / drug effects,  physiology*
Receptors, Serotonin, 5-HT3
Serotonin Antagonists / pharmacology*
Sodium Channels / drug effects,  genetics,  physiology*
Trans-Activators*
Transfection
Chemical
Reg. No./Substance:
0/Antiemetics; 0/Cation Transport Proteins; 0/DNA-Binding Proteins; 0/ERG protein, human; 0/ERG1 potassium channel; 0/Ether-A-Go-Go Potassium Channels; 0/Indoles; 0/KCNH6 protein, human; 0/KCNQ Potassium Channels; 0/KCNQ1 Potassium Channel; 0/KCNQ1 protein, human; 0/Potassium Channels; 0/Potassium Channels, Voltage-Gated; 0/Quinolizines; 0/Receptors, Serotonin; 0/Receptors, Serotonin, 5-HT3; 0/Serotonin Antagonists; 0/Sodium Channels; 0/Trans-Activators; 109889-09-0/Granisetron; 115956-13-3/dolasetron mesylate; 99614-02-5/Ondansetron

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