Document Detail

No involvement of nitric oxide in the limitation of beta-adrenergic inotropic responsiveness during ischemia.
MedLine Citation:
PMID:  11709404     Owner:  NLM     Status:  MEDLINE    
We tested whether or not endogenous nitric oxide (NO) attenuates beta-adrenergic inotropic responsiveness during normoperfusion or moderate myocardial ischemia. In 13 anesthetized pigs with a cannulated left anterior descending (LAD) coronary artery, the maximal contractile responses to intracoronary dobutamine and calcium were assessed during normoperfusion and at the end of a 90-min period of moderate ischemia (50% reduction in coronary arterial inflow) without (group 1, n = 6) and with (group 2, n = 7) prior inhibition of NO synthesis [30 mg/kg iv N(omega)-nitro-L-arginine (L-NNA)]. Contractile function was assessed by a regional work index (sonomicrometry, micromanometry, mm. mmHg). In groups 1 and 2 during normoperfusion, the maximal increase of the work index was greater with calcium than with dobutamine. At the end of ischemia in group 1, the baseline work index was decreased by approximately 50%, and the subsequent maximal increase of the work index with dobutamine, but not with calcium, was reduced compared with normoperfusion. In group 2 during normoperfusion, L-NNA did not alter the maximal increases of the work index with dobutamine or calcium. At the end of ischemia, the baseline work index was reduced by 64%, and the subsequent maximal increases of the work index with both dobutamine and calcium were reduced compared with normoperfusion; however, the response to calcium was still greater than that to dobutamine. We conclude that endogenous NO does not limit beta-adrenergic inotropic responsiveness in normoperfused or moderately ischemic porcine myocardium.
H Post; R Schulz; P Gres; G Heusch
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  American journal of physiology. Heart and circulatory physiology     Volume:  281     ISSN:  0363-6135     ISO Abbreviation:  Am. J. Physiol. Heart Circ. Physiol.     Publication Date:  2001 Dec 
Date Detail:
Created Date:  2001-11-15     Completed Date:  2002-01-07     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  100901228     Medline TA:  Am J Physiol Heart Circ Physiol     Country:  United States    
Other Details:
Languages:  eng     Pagination:  H2392-7     Citation Subset:  IM    
Abeteilung für Pathophysiologie, Zentrum für Innere Medizin des Universitätklinikums Essen, Germany.
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MeSH Terms
Adrenergic beta-Agonists / pharmacology
Calcium / pharmacology
Dobutamine / pharmacology
Enzyme Inhibitors / pharmacology
Heart Rate / physiology
Myocardial Contraction / drug effects,  physiology*
Myocardial Ischemia / metabolism*
Myocardium / metabolism
Nitric Oxide / metabolism*
Nitroarginine / pharmacology
Oxygen Consumption / physiology
Receptors, Adrenergic, beta / metabolism*
Swine, Miniature
Reg. No./Substance:
0/Adrenergic beta-Agonists; 0/Enzyme Inhibitors; 0/Receptors, Adrenergic, beta; 10102-43-9/Nitric Oxide; 2149-70-4/Nitroarginine; 34368-04-2/Dobutamine; 7440-70-2/Calcium

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