Document Detail


Cerebral vasodilatation to exogenous NO is a measure of fitness for life at altitude.
MedLine Citation:
PMID:  16763189     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
BACKGROUND AND PURPOSE: Andean highlanders, unlike Ethiopians, develop chronic mountain sickness (CMS), a maladaptation to their native land. Ambient hypoxia induces NO-mediated vasodilatation. Fitness for life at altitude might be revealed by cerebrovascular responses to NO. METHODS: Nine altitude-native men were examined at 3622 and 794 m in Ethiopia and compared with 9 altitude-native Andean men tested at 4338 and 150 m in Peru. We assessed CMS scores, hematocrits, end-tidal pressure of carbon dioxide (P(ET)co2), oxygen saturations, and cerebral blood flow velocity (CBV). We evaluated fitness for life at altitude from the cerebrovascular response to an exogenous NO donor. RESULTS: At high altitude, CMS scores and hematocrits were higher in Andeans, and they had lower oxygen saturations. Ethiopians had higher P(ET)co2 at all study sites. At low altitude, saturations were similar in both groups. Responsiveness of the cerebral circulation to NO was minimal in Ethiopians at low altitude, whereas Andeans had a large response. In contrast, at high altitude, Ethiopians showed large responses, and Peruvians had minimal responses. CONCLUSIONS: By our measure, high altitude-native Peruvians were well-adapted lowlanders, whereas Ethiopian highlanders were well adapted to altitude life. Environmental pressures were sufficient for human adaptation to chronic hypoxia in Africa but not South America. The mechanisms underlying these differences are unknown, although studies of neurovascular diseases suggest that this may be related to a NO receptor polymorphism.
Authors:
Otto Appenzeller; Victoria E Claydon; Giosué Gulli; Clifford Qualls; Marat Slessarev; Guta Zenebe; Amha Gebremedhin; Roger Hainsworth
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Publication Detail:
Type:  Comparative Study; Journal Article; Research Support, Non-U.S. Gov't     Date:  2006-06-08
Journal Detail:
Title:  Stroke; a journal of cerebral circulation     Volume:  37     ISSN:  1524-4628     ISO Abbreviation:  Stroke     Publication Date:  2006 Jul 
Date Detail:
Created Date:  2006-06-27     Completed Date:  2006-07-18     Revised Date:  2009-11-19    
Medline Journal Info:
Nlm Unique ID:  0235266     Medline TA:  Stroke     Country:  United States    
Other Details:
Languages:  eng     Pagination:  1754-8     Citation Subset:  IM    
Affiliation:
Department of Neurology, New Mexico Health Enhancement and Marathon Clinics (NMHEMC) Research Foundation, Albuquerque, NM 87122-1424, USA. oarun@unm.edu
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MeSH Terms
Descriptor/Qualifier:
Acclimatization / physiology*
Adult
African Continental Ancestry Group* / genetics
Altitude Sickness / epidemiology,  ethnology,  physiopathology*
Blood Flow Velocity
Breath Tests
Carbon Dioxide / analysis
Cerebrovascular Circulation / drug effects*
Ethiopia / epidemiology
Hematocrit
Humans
Hypoxia, Brain / ethnology,  etiology,  physiopathology*
Indians, South American* / genetics
Isosorbide Dinitrate / diagnostic use*,  pharmacology
Male
Nitric Oxide / physiology
Nitric Oxide Donors / diagnostic use*,  pharmacology
Nitroglycerin / diagnostic use*,  pharmacology
Oxygen / blood
Peru / epidemiology,  ethnology
Physical Fitness
Selection, Genetic
Chemical
Reg. No./Substance:
0/Nitric Oxide Donors; 10102-43-9/Nitric Oxide; 124-38-9/Carbon Dioxide; 55-63-0/Nitroglycerin; 7782-44-7/Oxygen; 87-33-2/Isosorbide Dinitrate

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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