Document Detail

A patch-clamp study of the effects of cicletanine on whole-cell calcium current in ventricular myocytes.
MedLine Citation:
PMID:  2458218     Owner:  NLM     Status:  MEDLINE    
The effects of extracellular application of cicletanine on the voltage-sensitive calcium current (ICa) was studied in isolated cells from frog ventricle. Myocytes were isolated by enzymatic dissociation and ICa was measured using the whole-cell configuration of the patch-clamp technique modified to permit intracellular perfusion with various substances. Cicletanine (10 to 100 microM) had no effect on control ICa. However, when ICa was enhanced by superfusion of the cell with saturating doses of beta-adrenergic agonist (isoprenaline, 2 microM) or by intracellular perfusion with maximal doses of cAMP (20 microM), cicletanine exerted a dual effect on ICa. At 10 microM, cicletanine generally induced a transient or sustained stimulation of ICa (5 to 40%), while 100 microM of the drug generally reduced ICa. The effects of cicletanine were reversible and not voltage-dependent. These results suggest that cicletanine affects ICa by acting on a mechanism occurring after cAMP synthesis, by enhancing cAMP concentration (e.g. through an inhibition of cAMP phosphodiesterase) or facilitating cAMP-dependent phosphorylation of the Ca channels.
M P Gisbert; P F Mery; R Fischmeister
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Drugs under experimental and clinical research     Volume:  14     ISSN:  0378-6501     ISO Abbreviation:  Drugs Exp Clin Res     Publication Date:  1988  
Date Detail:
Created Date:  1988-10-24     Completed Date:  1988-10-24     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  7802135     Medline TA:  Drugs Exp Clin Res     Country:  SWITZERLAND    
Other Details:
Languages:  eng     Pagination:  109-15     Citation Subset:  IM    
Laboratory of Cardiac Cellular Physiology, INSERM U-241, Paris-Sud University, Orsay, France.
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MeSH Terms
Antihypertensive Agents / pharmacology*
Calcium / metabolism*
Cyclic AMP / metabolism
Diuretics / pharmacology*
Electric Conductivity
Ion Channels / drug effects*,  metabolism
Myocardium / cytology,  metabolism*
Rana esculenta
Time Factors
Reg. No./Substance:
0/Antihypertensive Agents; 0/Diuretics; 0/Ion Channels; 0/Pyridines; 60-92-4/Cyclic AMP; 7440-70-2/Calcium; 87520-10-3/cycletanide

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