Journal article
Rapid-onset vasodilator responses to exercise in humans: Effect of increased baseline blood flow
Experimental physiology, Vol.105(1), pp.88-95
01/01/2020
DOI: 10.1113/EP088227
PMCID: PMC6938538
PMID: 31762131
Abstract
New Findings
What is the central question of this study?What is the effect of an elevated baseline blood flow, induced by high-dose intra-arterial infusion of either adenosine or ATP, on the rapid-onset vasodilatory response to a single forearm muscle contraction? What is the main finding and its importance?The peak response to a single contraction is unaffected by augmented baseline blood flow, and thus, is likely to be attributable to a feedforward vasodilatory mechanism. The hyperaemic responses to single muscle contractions are proportional to exercise intensity, which, in turn, is proportional to tissue metabolic demand. Hence, we tested the hypothesis that the rapid-onset vasodilatory response after a single muscle contraction would be unaffected when baseline blood flow was increased via high-dose intra-arterial infusion of either adenosine (ADO) or ATP. Twenty-four healthy young participants (28 +/- 1 years) performed a single forearm contraction (20% maximal voluntary contraction) 75 min after commencement of a continuous infusion of ADO (n = 6), ATP (n = 8) or saline (control; n = 10). Brachial artery diameter and blood velocity were measured using Doppler ultrasound. Resting forearm vascular conductance (FVC; in millilitres per minute per 100 mmHg per decilitre of forearm volume) was significantly higher during ADO (33 +/- 17) and ATP infusion (33 +/- 17) compared with the control infusion (8 +/- 3; P < 0.05). The peak FVCs post-contraction during ADO and ATP infusions were significantly greater than during the control infusion (P < 0.05), but not different from one another. The peak change in FVC from baseline was similar in all three conditions (control, 14 +/- 1; ADO, 24 +/- 2; and ATP, 23 +/- 6; P = 0.15). Total FVC (area under the curve) did not differ significantly between ADO and ATP (333 +/- 69 and 440 +/- 125); however, total FVC during ATP infusion was significantly greater compared with the control value (150 +/- 19; P < 0.05). We conclude that the peak response to a single contraction is unaffected by augmented baseline blood flow and is therefore likely to be attributable to a feedforward vasodilatory mechanism.
Details
- Title: Subtitle
- Rapid-onset vasodilator responses to exercise in humans: Effect of increased baseline blood flow
- Creators
- Gabrielle A. Dillon - Mayo Clinic in FloridaJohn R. A. Shepherd - Mayo ClinicDarren P. Casey - University of IowaFrank A. Dinenno - Colorado State UniversityTimothy B. Curry - Mayo Clinic in FloridaMichael J. Joyner - Mayo ClinicSushant M. Ranadive - University of Maryland, College Park
- Resource Type
- Journal article
- Publication Details
- Experimental physiology, Vol.105(1), pp.88-95
- DOI
- 10.1113/EP088227
- PMID
- 31762131
- PMCID
- PMC6938538
- NLM abbreviation
- Exp Physiol
- ISSN
- 0958-0670
- eISSN
- 1469-445X
- Publisher
- Wiley
- Number of pages
- 8
- Grant note
- UL1 TR00013 / CTSA; United States Department of Health & Human Services; National Institutes of Health (NIH) - USA; NIH National Center for Advancing Translational Sciences (NCATS) HL-119337; HL-105467 / US National Institutes of Health; United States Department of Health & Human Services; National Institutes of Health (NIH) - USA The Caywood Professorship via theMayo Foundation
- Language
- English
- Date published
- 01/01/2020
- Academic Unit
- Physical Therapy and Rehabilitation Science; Fraternal Order of Eagles Diabetes Research Center
- Record Identifier
- 9984294948702771
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