Document Detail


Evidence against significant resting sympathetic coronary vasoconstrictor tone in the conscious dog.
MedLine Citation:
PMID:  7273359     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
The primary objective of this study was to ascertain whether resting coronary blood flow is under tonic restraint due to sympathetically mediated alpha-adrenergic coronary vasoconstriction. To accomplish this, we first developed and verified a technique for selectively sympathectomizing the posterior region of the canine left ventricle. This technique entailed the topical application of phenol in a thin line to specific sites on the myocardium and epicardial vessels. As part of the verification, we demonstrated that left stellate nerve stimulation caused increases in the myocardial extraction ratios for oxygen and lactate in the normally innervated region (I) of the ventricle, but not in the sympathectomized region (Sx). We then measured regional myocardial blood flow with microspheres in phenol-treated animals under conscious, resting conditions. The animals were acclimated to the laboratory environment, and their arterial plasma norepinephrine levels averaged 135 +/- 37 pg/ml. heart rate (81 +/- 3 bpm) and mean aortic pressure (100 +/- 2 mm Hg) were not significantly affected by beta-adrenergic blockade or combined alpha- and beta-adrenergic blockade in these animals. Blood flow in I and Sx averaged 0.87 +/- 0.08 ml/min per g and 0.85 +/- 0.07 ml/min per g, respectively, and the difference was not statistically significant. The endocardial-to-epicardial blood flow ratio in I and Sx averaged 1.23 +/- 0.03 and 1.29 +/- 0.04, respectively, and the difference was not statistically significant. The results were not significantly affected by beta-adrenergic blockade or combined alpha- and beta-adrenergic blockade. We were unable to confirm previous evidence in the literature of significant resting sympathetic coronary vasoconstrictor tone in the conscious animal.
Authors:
W M Chilian; R B Boatwright; T Shoji; D M Griggs
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Publication Detail:
Type:  Journal Article; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  Circulation research     Volume:  49     ISSN:  0009-7330     ISO Abbreviation:  Circ. Res.     Publication Date:  1981 Oct 
Date Detail:
Created Date:  1981-11-22     Completed Date:  1981-11-22     Revised Date:  2007-11-14    
Medline Journal Info:
Nlm Unique ID:  0047103     Medline TA:  Circ Res     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  866-76     Citation Subset:  IM    
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MeSH Terms
Descriptor/Qualifier:
Animals
Coronary Circulation / drug effects*
Dogs
Lactates / metabolism
Lactic Acid
Male
Myocardium / metabolism
Norepinephrine / metabolism
Oxygen / metabolism
Phenols / pharmacology
Regional Blood Flow
Rest
Sympathomimetics / pharmacology*
Vasoconstriction / drug effects*
Grant Support
ID/Acronym/Agency:
R01-HL 11876/HL/NHLBI NIH HHS; T32-HL 07094/HL/NHLBI NIH HHS
Chemical
Reg. No./Substance:
0/Lactates; 0/Phenols; 0/Sympathomimetics; 50-21-5/Lactic Acid; 51-41-2/Norepinephrine; 7782-44-7/Oxygen

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


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