Document Detail

Actions of adenosine on the sinus node.
MedLine Citation:
PMID:  3588609     Owner:  NLM     Status:  MEDLINE    
Adenosine has a negative chronotropic effect on pacemaker tissue. This is a direct effect on pacemaker cells and is mediated by extracellular adenosine receptors (i.e., A1 subtype). Adenosine also produces a shift in pacemaker site. There is a hierarchy in sensitivity of pacemakers to adenosine with the lower, i.e., His bundle, pacemaker being most sensitive. The pacemaker slowing caused by adenosine is due to a hyperpolarization of the membrane which results in a decrease in phase 4 depolarization. The hyperpolarization is presumably the result of an adenosine-activated K+ conductance. Adenosine and acetylcholine have similar effects, being additive up to a maximal response, and may be the result of activation of the same K+ channels via different receptors. Adenosine may be important in modulating several bradyarrhythmias seen clinically. Future studies will help to determine more precisely the mechanism of action of adenosine at the molecular level as well as the involvement of adenosine in pacemaker function during normal and abnormal conditions.
G A West
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Publication Detail:
Type:  In Vitro; Journal Article    
Journal Detail:
Title:  Progress in clinical and biological research     Volume:  230     ISSN:  0361-7742     ISO Abbreviation:  Prog. Clin. Biol. Res.     Publication Date:  1987  
Date Detail:
Created Date:  1987-06-26     Completed Date:  1987-06-26     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  7605701     Medline TA:  Prog Clin Biol Res     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  97-108     Citation Subset:  IM    
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MeSH Terms
Acetylcholine / pharmacology
Action Potentials / drug effects
Adenosine / pharmacology*
Guinea Pigs
Heart Rate / drug effects
Membrane Potentials / drug effects
Sinoatrial Node / drug effects,  physiology*
Reg. No./Substance:
51-84-3/Acetylcholine; 58-61-7/Adenosine

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

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