α-Adrenergic vasoconstrictor responsiveness is preserved in the heated human leg
Keller DM, Sander M, Stallknecht B, Crandall CG
The Journal of physiology · 49 citations
How it was studied
- Design
- Controlled clinical trial (classified by our AI screen)
- Studied in
- People
- Main outcome
- Health markers and function
Who paid for it
- Funding
- Independent funding
- University or hospital
- Hospital Research Foundation
- Government
- Danmarks Grundforskningsfond
- Government
- National Institutes of Health
- Government
- U.S. Public Health Service
- Government
- National Heart, Lung, and Blood Institute
- Government
- NHLBI NIH HHS
- Government
- PHS HHS
- Grants
- National Heart, Lung, and Blood Institute (R01 HL084072); U.S. Public Health Service (NHLBI 61388); U.S. Public Health Service (NHLBI 082426); National Heart, Lung, and Blood Institute (R01HL061388); U.S. Public Health Service (84072)
Based on 7 listed funder(s).
Publication
- Published
- 2010-08-06 · J Physiol · vol. 588 · issue 19 · pp. 3799–3808
- Publisher
- Wiley
- Cited
- 63 citations · more than 89% of similar papers · 2.4× the field average
- References
- 80 works
- Access
- Open access (repository copy)
- Research areas
- Heart Rate Variability and Autonomic Control · Hemodynamic Monitoring and Therapy · Thermoregulation and physiological responses
- Keywords
- Vasoconstriction, Femoral artery, Phenylephrine, Medicine, Vasodilation, Anesthesia, Blood flow, Blood pressure, Chemistry, Internal medicine
- MeSH
- leg, muscle, skeletal, humans, xenon radioisotopes, phenylephrine, azepines, receptors, adrenergic, alpha, adrenergic alpha-agonists, ultrasonography, doppler, body temperature, blood pressure, regional blood flow, vasoconstriction, dose-response relationship, drug, adult, male, hot temperature, young adult, adrenergic alpha-1 receptor agonists, adrenergic alpha-2 receptor antagonists
4 authors
From US, DK
- David M. KellerThe University of Texas at Arlington; Presbyterian Hospital; Institute for Exercise and Environmental Medicine
- Mikael Sander
- Bente Merete StallknechtUniversity of Copenhagen
- Craig G. Crandall · correspondingPresbyterian Hospital; Institute for Exercise and Environmental Medicine; The University of Texas Southwestern Medical Center
Abstract
This study tested the hypothesis that passive leg heating attenuates α-adrenergic vasoconstriction within that limb. Femoral blood flow (FBF, femoral artery ultrasound Doppler) and femoral vascular conductance (FVC, FBF/mean arterial blood pressure), as well as calf muscle blood flow (CalfBF, ¹³³xenon) and calf vascular conductance (CalfVC) were measured during intra-arterial infusion of an α₁-adrenoreceptor agonist, phenylephrine (PE, 0.025 to 0.8 μg kg₋₁ min₋₁) and an α₂-adrenoreceptor agonist, BHT-933 (1.0 to 10 μg kg₋₁ min₋₁) during normothermia and passive leg heating (water-perfused pant leg). Passive leg heating (∼46◦C water temperature) increased FVC from 4.5 ± 0.5 to 11.9 ± 1.3 ml min₋₁ mmHg₋₁ (P < 0.001). Interestingly, CalfBF (1.8±0.2 vs. 2.8±0.3mlmin₋₁ (100 g)₋₁) and CalfVC (2.0±0.3 vs. 3.9±0.5mlmin₋₁ (100 g)₋₁ mmHg₋₁ ×100) were also increased by this perturbation (P <0.05 for both). Infusion of PE and BHT-933 resulted in greater absolute decreases in FVC during leg heating compared to normothermic conditions (maximal decreases in FVC during heating vs. normothermia: PE: 7.8 ± 1.1 vs. 2.8 ± 0.5 ml min₋₁ mmHg₋₁; BHT-933: 8.6 ± 1.7 vs. 2.1 ± 0.4 ml min₋₁ mmHg₋₁; P < 0.01 for both). However, the nadir FVC during drug infusion was higher during passive leg heating compared to normothermic conditions (FVC at highest dose of respective drugs during heating vs. normothermic conditions: PE: 3.7 ± 0.4 vs. 2.0 ± 0.3 ml min₋₁ mmHg₋₁; BHT-933: 3.8 ± 0.2 vs. 2.1 ± 0.3 ml min₋₁ mmHg₋₁; P < 0.001 for both). Leg heating did not alter the responsiveness of CalfBF or CalfVC to either PE or BHT-933. Taken together, these observations suggest that local heating does not decrease α-adrenergic responsiveness.However, heat-induced vasodilatation opposes α-adrenergic vasoconstriction. Furthermore, passive heating of a limb causes not only an increase in skin blood flow but also in muscle blood flow.
Abstract via Europe PMC. Copyright remains with the authors or publisher.
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