Document Detail

Caffeine stimulates the reverse mode of Na/Ca2+ exchanger in ferret ventricular muscle.
MedLine Citation:
PMID:  11437737     Owner:  NLM     Status:  MEDLINE    
This study investigated the effect of caffeine on the sarcolemmal mechanisms involved in intracellular calcium control. Ferret cardiac preparations were treated with ryanodine and thapsigargin in order to eliminate the sarcoplasmic reticulum (SR) function. This treatment abolished caffeine contracture irreversibly in normal solution. The perfusion with K-free medium that blocked the Na+--K+ pump resulted in a recovery of slow relaxing caffeine contractures similar to Na-free contractures. The amplitude of caffeine contractures was dependent on the bathing [caffeine]o and [Ca2+]o. Divalent cations Ni2+ and Cd2+, which have an inhibitory effect on the Na+/Ca2+ exchanger, produced dose-dependent inhibition of caffeine responses with apparent Ki of 780 +/- 19 and 132 +/- 5 microM, respectively. Caffeine also caused dose-dependent inhibition of Na-free contractures (Ki=4.62 +/- 1.5 mM), and the reduction or removal of [Na+]o exerted an inhibitory effect on caffeine contractures (Ki=73.5 +/- 17.12 mM). These experiments indicate that the increase in resting tension following exposure to caffeine was mediated by Na+/Ca2+ exchanger, which represents an additional element of complexity in caffeine action on cardiac muscle.
C Léoty; C Huchet-Cadiou; S Talon; S Choisy; W Hleihel
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Publication Detail:
Type:  In Vitro; Journal Article    
Journal Detail:
Title:  Acta physiologica Scandinavica     Volume:  172     ISSN:  0001-6772     ISO Abbreviation:  Acta Physiol. Scand.     Publication Date:  2001 May 
Date Detail:
Created Date:  2001-07-04     Completed Date:  2001-08-30     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  0370362     Medline TA:  Acta Physiol Scand     Country:  England    
Other Details:
Languages:  eng     Pagination:  27-37     Citation Subset:  IM    
Laboratoire de Physiologie Générale, Faculté des Sciences et des Techniques, Nantes, France.
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MeSH Terms
Caffeine / pharmacology*
Calcium / pharmacology
Dose-Response Relationship, Drug
Heart Ventricles / drug effects*,  metabolism
Myocardial Contraction / drug effects*
Myocardium / metabolism*
Potassium / pharmacology
Ryanodine / pharmacology
Sarcoplasmic Reticulum / drug effects
Sodium-Calcium Exchanger / metabolism*
Thapsigargin / pharmacology
Reg. No./Substance:
0/Sodium-Calcium Exchanger; 15662-33-6/Ryanodine; 58-08-2/Caffeine; 67526-95-8/Thapsigargin; 7440-09-7/Potassium; 7440-70-2/Calcium

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

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