Document Detail


Inhibitory effect of thiopental on ultra-rapid delayed rectifier K+ current in H9c2 cells.
MedLine Citation:
PMID:  16217144     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Using the whole-cell voltage clamp technique, we investigated the effects of thiopental on membrane currents in H9c2 cells, a cell line derived from embryonic rat heart. Thiopental blocked a rapidly activating, very slowly-inactivating ultra-rapid type I(Kur)-like outward K(+) current in a concentration-dependent manner. The half-maximal concentration (IC(50)) of thiopental was 97 microM with a Hill coefficient of 1.2. The thiopental-sensitive current was also blocked by high concentrations of nifedipine (IC(50) = 9.1 microM) and 100 microM chromanol 293B, a blocker of slowly activating delayed rectifier K+ current (I(Ks)), but was insensitive to E-4031, an inhibitor of rapidly activating delayed rectifier K(+) current (I(Kr)). TEA (tetraethylammonium) at 5 mM and 4-AP (4-aminopiridine) at 1 mM reduced the K(+) current to 30.8 +/- 12.2% and 20.5 +/- 6.5% of the control, respectively. Using RT-PCR, we detected mRNAs of Kv2.1, Kv3.4, Kv4.1, and Kv4.3 in H9c2 cells. Among those, Kv2.1 and Kv3.4 have I(Kur)-type kinetics and are therefore candidates for thiopental-sensitive K(+) channels in H9c2 cells. This is the first report showing that thiopental inhibits I(Kur). This effect of thiopental may be involved in its reported prolongation of cardiac action potentials.
Authors:
Hideki Suzuki; Nobuo Momoi; Tomoyuki Ono; Sachiko Maeda; Yayoi Shikama; Isao Matsuoka; Hitoshi Suzuki; Junko Kimura
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Publication Detail:
Type:  Journal Article     Date:  2005-10-08
Journal Detail:
Title:  Journal of pharmacological sciences     Volume:  99     ISSN:  1347-8613     ISO Abbreviation:  J. Pharmacol. Sci.     Publication Date:  2005 Oct 
Date Detail:
Created Date:  2005-10-18     Completed Date:  2006-05-03     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  101167001     Medline TA:  J Pharmacol Sci     Country:  Japan    
Other Details:
Languages:  eng     Pagination:  177-84     Citation Subset:  IM    
Affiliation:
Department of Pediatrics, Fukushima Medical University, School of Medicine, Fukushima 960-1295, Japan.
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MeSH Terms
Descriptor/Qualifier:
Anesthetics / pharmacology*
Animals
Cell Line
Chromans / pharmacology
Delayed Rectifier Potassium Channels / antagonists & inhibitors*,  genetics,  metabolism
Kinetics
Membrane Potentials / drug effects
Myocytes, Cardiac
Nifedipine / pharmacology
Potassium / metabolism*
Potassium Channel Blockers / pharmacology
RNA, Messenger / metabolism
Rats
Shab Potassium Channels / drug effects*,  genetics,  metabolism
Shaw Potassium Channels / drug effects*,  genetics,  metabolism
Sulfonamides / pharmacology
Thiopental / pharmacology*
Chemical
Reg. No./Substance:
0/Anesthetics; 0/Chromans; 0/Delayed Rectifier Potassium Channels; 0/Kv3.4 protein, rat; 0/Potassium Channel Blockers; 0/RNA, Messenger; 0/Shab Potassium Channels; 0/Shaw Potassium Channels; 0/Sulfonamides; 163163-23-3/6-cyano-4-(N-ethylsulfonyl-N-methylamino)-3-hydroxy-2,2-dimethylchromane; 21829-25-4/Nifedipine; 7440-09-7/Potassium; 76-75-5/Thiopental

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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