| Nitric oxide-mediated vasodilation becomes independent of beta-adrenergic receptor activation with increased intensity of hypoxic exercise. | |
| | |
MedLine Citation:
|
PMID: 21193565 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
|
Hypoxic vasodilation in skeletal muscle at rest is known to include β-adrenergic receptor-stimulated nitric oxide (NO) release. We previously reported that the augmented skeletal muscle vasodilation during mild hypoxic forearm exercise includes β-adrenergic mechanisms. However, it is unclear whether a β-adrenergic receptor-stimulated NO component exists during hypoxic exercise. We hypothesized that NO-mediated vasodilation becomes independent of β-adrenergic receptor activation with increased exercise intensity during hypoxic exercise. Ten subjects (7 men, 3 women; 23 ± 1 yr) breathed hypoxic gas to titrate arterial O(2) saturation to 80% while remaining normocapnic. Subjects performed two consecutive bouts of incremental rhythmic forearm exercise (10% and 20% of maximum) with local administration (via a brachial artery catheter) of propranolol (β-adrenergic receptor inhibition) alone and with the combination of propranolol and nitric oxide synthase inhibition [N(G)-monomethyl-l-arginine (l-NMMA)] under normoxic and hypoxic conditions. Forearm blood flow (FBF, ml/min; Doppler ultrasound) and blood pressure [mean arterial pressure (MAP), mmHg; brachial artery catheter] were assessed, and forearm vascular conductance (FVC, ml·min(-1)·100 mmHg(-1)) was calculated (FBF/MAP). During propranolol alone, the rise in FVC (Δ from normoxic baseline) due to hypoxic exercise was 217 ± 29 and 415 ± 41 ml·min(-1)·100 mmHg(-1) (10% and 20% of maximum, respectively). Combined propranolol-l-NMMA infusion during hypoxic exercise attenuated ΔFVC at 20% (352 ± 44 ml·min(-1)·100 mmHg(-1); P < 0.001) but not at 10% (202 ± 28 ml·min(-1)·100 mmHg(-1); P = 0.08) of maximum compared with propranolol alone. These data, when integrated with earlier findings, demonstrate that NO contributes to the compensatory vasodilation during mild and moderate hypoxic exercise; a β-adrenergic receptor-stimulated NO component exists during low-intensity hypoxic exercise. However, the source of the NO becomes less dependent on β-adrenergic mechanisms as exercise intensity increases. |
| | |
Authors:
|
Darren P Casey; Timothy B Curry; Brad W Wilkins; Michael J Joyner |
Related Documents
:
|
6893195 - Control of luteal function and implantation in the mink by prolactin. 21305485 - Abnormal heart rate recovery after exercise predicts coronary artery disease severity. 3024055 - Exercise-induced increases in plasma catecholamines and growth hormone are augmented by... 11817995 - Diagnosis of overtraining: what tools do we have? 1145535 - Comparison of the bronchial response to running and cycling in asthma using an improved... 12076465 - Rehabilitation after lumbar disc surgery. |
Publication Detail:
|
Type: Journal Article; Research Support, N.I.H., Extramural; Research Support, Non-U.S. Gov't Date: 2010-12-30 |
Journal Detail:
|
Title: Journal of applied physiology (Bethesda, Md. : 1985) Volume: 110 ISSN: 1522-1601 ISO Abbreviation: J. Appl. Physiol. Publication Date: 2011 Mar |
Date Detail:
|
Created Date: 2011-03-09 Completed Date: 2011-07-07 Revised Date: 2012-03-01 |
Medline Journal Info:
|
Nlm Unique ID: 8502536 Medline TA: J Appl Physiol Country: United States |
Other Details:
|
Languages: eng Pagination: 687-94 Citation Subset: IM |
Affiliation:
|
Dept. of Anesthesiology, Mayo Clinic, 200 First St. SW, Rochester, MN 55905, USA. casey.darren@mayo.edu |
Export Citation:
|
APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
|
Anoxia
/
physiopathology* Female Humans Male Nitric Oxide / blood* Physical Exertion* Receptors, Adrenergic, beta / metabolism* Vasodilation* Young Adult |
| Grant Support | |
ID/Acronym/Agency:
|
AR-55819/AR/NIAMS NIH HHS; HL-46493/HL/NHLBI NIH HHS; RR-024150/RR/NCRR NIH HHS |
| Chemical | |
Reg. No./Substance:
|
0/Receptors, Adrenergic, beta; 10102-43-9/Nitric Oxide |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
Previous Document: Associations between sports participation, cardiorespiratory fitness and adiposity in young adult tw...
Next Document: Effect of daily noise exposure monitoring on annual rates of hearing loss in industrial workers.