Document Detail

Altered electrical response to caffeine exposure in hypertrophied rat myocardium.
MedLine Citation:
PMID:  2534058     Owner:  NLM     Status:  MEDLINE    
We investigated the electrophysiological effects of cardiac hypertrophy induced by different experimental models. Comparison of the action potentials of hypertrophied and control rat hearts reveals a pronounced prolongation of the action potential for all types of hypertrophy. This prolongation affects the entire repolarization phase of the action potential 8 days after severe aortic constriction, after 8 days of isoproterenol treatment (5 mg/kg per day), and 3 months after an aortocaval fistula. The electrical changes associated with myocardial hypertrophy induced by pressure overload (aortic constriction) were compared with those resulting from volume overload (aortocaval fistula). Our results show that action potential alterations depend on the nature, duration, and severity of the work load. Thus, pressure overload is more potent to induce these modifications. In the hearts subjected to pressure overload, action potential alterations appear more rapidly and are more marked for the same degree of hypertrophy than those of the volume-hypertrophied myocardium. Furthermore, such data also demonstrate that the early alteration of the action potential during the development of compensatory hypertrophy is a prolongation of the later phase of repolarization (phase 3), without prolongation of the other repolarization phases (1 and 2). This change appears 3 days after aortic constriction, 1 month after coronary artery ligation (in the healthy part of the left ventricle), and 1 month after an aortocaval fistula.(ABSTRACT TRUNCATED AT 250 WORDS)
C Thollon; P Kreher
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Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  Canadian journal of physiology and pharmacology     Volume:  67     ISSN:  0008-4212     ISO Abbreviation:  Can. J. Physiol. Pharmacol.     Publication Date:  1989 Dec 
Date Detail:
Created Date:  1990-04-23     Completed Date:  1990-04-23     Revised Date:  2003-11-14    
Medline Journal Info:
Nlm Unique ID:  0372712     Medline TA:  Can J Physiol Pharmacol     Country:  CANADA    
Other Details:
Languages:  eng     Pagination:  1471-9     Citation Subset:  IM    
Laboratoire de physiologie cellulaire cardiaque, Université Joseph Fourier, URA CNRS 632, Grenoble, France.
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MeSH Terms
Action Potentials / drug effects
Caffeine / pharmacology*
Cardiomegaly / physiopathology*
Coronary Vessels / drug effects
Isoproterenol / pharmacology
Myocardial Contraction / drug effects
Myocardium / cytology
Rats, Inbred Strains
Sarcoplasmic Reticulum / drug effects
Reg. No./Substance:
58-08-2/Caffeine; 7683-59-2/Isoproterenol

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

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