| Control of coronary blood flow during exercise. | |
MedLine Citation:
|
PMID: 11910046 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
|
Under normal physiological conditions, coronary blood flow is closely matched with the rate of myocardial oxygen consumption. This matching of flow and metabolism is physiologically important due to the limited oxygen extraction reserve of the heart. Thus, when myocardial oxygen consumption is increased, as during exercise, coronary vasodilation and increased oxygen delivery are critical to preventing myocardial underperfusion and ischemia. Exercise coronary vasodilation is thought to be mediated primarily by the production of local metabolic vasodilators released from cardiomyocytes secondary to an increase in myocardial oxygen consumption. However, despite various investigations into this mechanism, the mediator(s) of metabolic coronary vasodilation remain unknown. As will be seen in this review, the adenosine, K(+)(ATP) channel and nitric oxide hypotheses have been found to be inadequate, either alone or in combination as multiple redundant compensatory mechanisms. Prostaglandins and potassium are also not important in steady-state coronary flow regulation. Other factors such as ATP and endothelium-derived hyperpolarizing factors have been proposed as potential local metabolic factors, but have not been examined during exercise coronary vasodilation. In contrast, norepinephrine released from sympathetic nerve endings mediates a feed-forward betaadrenoceptor coronary vasodilation that accounts for approximately 25% of coronary vasodilation observed during exercise. There is also a feed-forward alpha-adrenoceptor-mediated vasoconstriction that helps maintain blood flow to the vulnerable subendocardium when heart rate, myocardial contractility, and oxygen consumption are elevated during exercise. Control of coronary blood flow during pathophysiological conditions such as hypertension, diabetes mellitus, and heart failure is also addressed. |
Authors:
|
Johnathan D Tune; Keith Neu Richmond; Mark W Gorman; Eric O Feigl |
Related Documents
:
|
21979576 - Relationships between negative affect and academic achievement among secondary school s... 17558196 - Paraoxonase activity following exercise-based cardiac rehabilitation program. 18989536 - The effects of exercise capacity and sedentary lifestyle on haemostasis among middle-ag... 20543746 - Acute responses to high-intensity intermittent exercise in chd patients. 10721816 - Acute plasma volume expansion alters cardiovascular but not thermal function during mod... 7229366 - Marihuana and work performance: results from an experiment. |
Publication Detail:
|
Type: Journal Article; Review |
Journal Detail:
|
Title: Experimental biology and medicine (Maywood, N.J.) Volume: 227 ISSN: 1535-3702 ISO Abbreviation: Exp. Biol. Med. (Maywood) Publication Date: 2002 Apr |
Date Detail:
|
Created Date: 2002-03-22 Completed Date: 2002-04-12 Revised Date: 2005-11-16 |
Medline Journal Info:
|
Nlm Unique ID: 100973463 Medline TA: Exp Biol Med (Maywood) Country: United States |
Other Details:
|
Languages: eng Pagination: 238-50 Citation Subset: IM |
Affiliation:
|
Department of Integrative Physiology, University of North Texas Health Science Center, Fort Worth, Texas 76107, USA. jtune@hsc.unt.edu |
Export Citation:
|
APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
|
Animals Coronary Circulation / physiology* Exercise / physiology* Humans Myocardium / metabolism Oxygen Consumption |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
Previous Document: The potential of DNA vaccination against tumor-associated antigens for antitumor therapy.
Next Document: Systolic elastance and resistance in the regulation of cardiac pumping function in early streptozoto...