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
Related Documents :
8010029 - Electrophysiological effects of n6-cyclopentyl-adenosine and [-]-n6-[phenylisopropyl]-a...
9269779 - Role of a2a extracellular adenosine receptor-mediated signaling in adenosine-mediated i...
25199539 - Adenosine as a probing tool for the mechanistic study of acupuncture treatment.
19378379 - Roles of purines in synaptic modulation evoked by hypercapnia in isolated spinal cord o...
20723579 - Adenosine regulates sertoli cell function by activating ampk.
3011169 - Adenosine inhibits epileptiform activity arising in hippocampal area ca3.
4062429 - Cholinergic properties of choline ethers.
2376079 - Differential desensitization of a1 adenosine receptor-mediated inhibition of cardiac my...
10844009 - Dopamine-deficient mice are hypersensitive to dopamine receptor agonists.
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    
Export Citation:
APA/MLA Format     Download EndNote     Download BibTex
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

Previous Document:  Adenosine receptors: development of selective agonists and antagonists.
Next Document:  The use of a quantitative assay in endotoxin testing.