Document Detail


Taming the "Sleeping Giant": The Role of Endothelin-1 in the Regulation of Skeletal Muscle Blood Flow and Arterial Blood Pressure during Exercise.
MedLine Citation:
PMID:  23103494     Owner:  NLM     Status:  Publisher    
Abstract/OtherAbstract:
The cardiovascular response to exercise is governed by a combination of vasodilating and vasoconstricting influences that optimize exercising muscle perfusion while protecting mean arterial pressure (MAP). The degree to which endogenous endothelin-1 (ET-1), the body's most potent vasoconstrictor, participates in this response is unknown. Thus, in eight young (24 ± 2 yrs), healthy volunteers, we examined leg blood flow, MAP, tissue oxygenation, heart rate, leg arterial-venous oxygen difference (a-vO(2diff)), leg oxygen consumption (VO(2)), pH, and net ET-1 and lactate release at rest and during knee extensor exercise (0-5-10-15-20-30W) before and after intra-arterial infusion of BQ-123 (ETA receptor antagonist). At rest, BQ-123 did not evoke a change in leg blood flow or MAP. During exercise, net ET-1 release across the exercising leg increased ~3-fold. BQ-123 increased leg blood flow by ~20% across all work rates (Δ113 ± 76, Δ176 ± 83, Δ304 ± 108, Δ364 ± 130, Δ502 ± 117, and Δ570 ± 178 ml/min at 0-5-10-15-20-30W, respectively) and attenuated the exercise-induced increase in MAP by ~6%. The increase in leg blood flow was accompanied by a ~9% increase in leg VO(2) with unchanged a-vO(2diff) and deoxyhemoglobin, suggesting a decline in intramuscular efficiency following ETA receptor blockade. Together, these findings identify a significant role of the ET-1 pathway in the cardiovascular response to exercise, implicating vasoconstriction via the ETA receptor as an important mechanism for both the restraint of blood flow in the exercising limb and maintenance of MAP in healthy, young adults.
Authors:
Zachary Barrett-O'Keefe; Stephen J Ives; Joel Douglas Trinity; Richard Garrett Morgan; Matthew Jordan Rossman; Anthony J Donato; Sean Runnels; David E Morgan; Benjamin S Gmelch; Amber D Bledsoe; Russell S Richardson; D Walter Wray
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Publication Detail:
Type:  JOURNAL ARTICLE     Date:  2012-10-26
Journal Detail:
Title:  American journal of physiology. Heart and circulatory physiology     Volume:  -     ISSN:  1522-1539     ISO Abbreviation:  Am. J. Physiol. Heart Circ. Physiol.     Publication Date:  2012 Oct 
Date Detail:
Created Date:  2012-10-29     Completed Date:  -     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  100901228     Medline TA:  Am J Physiol Heart Circ Physiol     Country:  -    
Other Details:
Languages:  ENG     Pagination:  -     Citation Subset:  -    
Affiliation:
1University of Utah.
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