Document Detail


A method to evaluate the response of the coronary circulation of perfused rat heart to adenosine.
MedLine Citation:
PMID:  8723026     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Exogenous adenosine causes a monophasic dilation of the coronary vessels in paced, perfused rat heart preparations. Because levels of endogenous adenosine in paced hearts may mask the presence of high potency adenosine receptors, we have developed a method to measure coronary vascular responses in a potassium-arrested heart. Hearts from adult male, Wistar rats were perfused at a constant flow rate of 10 mL/min in the nonrecirculating, Langendorff mode, using Krebs-Henseleit buffer. After 30 min, coronary perfusion pressure was 44 +/- 1 mmHg (mean +/- SEM). Hearts were then perfused with a modified Krebs-Henseleit buffer containing 35 mM potassium. Coronary perfusion pressure increased by 84 +/- 3 mmHg. Adenosine-induced reductions in coronary perfusion pressure were expressed as a percentage of the maximal increase in pressure produced by modified Krebs-Henseleit buffer from the equilibration level. A concentration-response curve for adenosine (n = 6) was biphasic and best described by the presence of two adenosine receptors, with negative log EC50 values of 8.8 +/- 0.3 and 4.3 +/- 0.1, representing 29 +/- 3 and 71 +/- 3%, respectively, of the observed response. Interstitial adenosine sampled by microdialysis during potassium arrest was 25% of the concentration found in paced hearts. Endogenous adenosine in nonarrested hearts may obscure the biphasic response of the coronary vessels to adenosine.
Authors:
G J Harrison; F A Harden; L R Jordan; J I Varela; R J Willis
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Publication Detail:
Type:  Comparative Study; In Vitro; Journal Article    
Journal Detail:
Title:  Canadian journal of physiology and pharmacology     Volume:  74     ISSN:  0008-4212     ISO Abbreviation:  Can. J. Physiol. Pharmacol.     Publication Date:  1996 Feb 
Date Detail:
Created Date:  1997-04-03     Completed Date:  1997-04-03     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  0372712     Medline TA:  Can J Physiol Pharmacol     Country:  CANADA    
Other Details:
Languages:  eng     Pagination:  145-9     Citation Subset:  IM    
Affiliation:
Rotary Centre for Cardiovascular Research, School of Science, Griffith University, Nathan, Australia.
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MeSH Terms
Descriptor/Qualifier:
Adenosine / metabolism,  pharmacology*
Animals
Coronary Vessels / drug effects*
Dose-Response Relationship, Drug
Heart / physiology*
Histamine / pharmacology
Male
Myocardium / metabolism
Perfusion
Rats
Rats, Wistar
Receptors, Purinergic P1 / drug effects*
Sodium Nitrite / pharmacology
Vasodilator Agents / pharmacology*
Chemical
Reg. No./Substance:
0/Receptors, Purinergic P1; 0/Vasodilator Agents; 51-45-6/Histamine; 58-61-7/Adenosine; 7632-00-0/Sodium Nitrite

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


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