| Effects of high-altitude chronic hypoxia on platelet alpha 2-receptors in man. | |
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MedLine Citation:
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PMID: 9134380 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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During chronic high-altitude (HA) exposure, basal and exercise-induced noradrenaline (NA) increases do not parallel blood pressure (BP) changes observed; unlike beta-adrenergic receptors, to our knowledge no data are available on alpha-receptors. We studied platelet alpha 2- and leucocyte beta-receptors and basal catecholamine levels in 11 trained climbers before and after they had spent a 15-day period at a height of over 4400 m. In six of the climbers we also evaluated catecholamines after maximal bicycle ergometer exercise. After chronic high-altitude exposure, a significant decrease was found in platelet alpha 2-receptor density and affinity [Bmax from 92.6 +/- 6.7 to 54.6 +/- 4.2 fmol mg-1 protein (P < 0.001) and KD from 1.271 +/- 0.034 to 1.724 +/- 0.077 nmol L-1 (P < 0.05)], although no changes to beta-receptors were observed. No changes were found in basal pre- and post-expedition NA and adrenaline (A), and there was only a slight decrease in post-expedition NA after maximal exercise. Our results suggest that prolonged exposure to hypoxia induces a down-regulation of alpha 2-receptors, which may be a contributory factor in the regulation of the physiological vascular response to acclimatization. |
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Authors:
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M Zaccaria; P A Borea; G Opocher; A Ponchia; K Varani; D Fraccarollo; C Scandellari |
Publication Detail:
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Type: Journal Article; Research Support, Non-U.S. Gov't |
Journal Detail:
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Title: European journal of clinical investigation Volume: 27 ISSN: 0014-2972 ISO Abbreviation: Eur. J. Clin. Invest. Publication Date: 1997 Apr |
Date Detail:
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Created Date: 1997-06-26 Completed Date: 1997-06-26 Revised Date: 2006-11-15 |
Medline Journal Info:
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Nlm Unique ID: 0245331 Medline TA: Eur J Clin Invest Country: ENGLAND |
Other Details:
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Languages: eng Pagination: 316-21 Citation Subset: IM; S |
Affiliation:
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Division of Internal Medicine (Sports Medicine Unit), University of Padua, Italy. |
Export Citation:
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APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
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Adult Altitude* Anoxia / blood* Chronic Disease Exercise Female Humans Male Norepinephrine / blood Receptors, Adrenergic, alpha-2 / blood* |
| Chemical | |
Reg. No./Substance:
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0/Receptors, Adrenergic, alpha-2; 51-41-2/Norepinephrine |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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