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Titolo:
THE BRAIN AT HIGH-ALTITUDE - HYPOMETABOLISM AS A DEFENSE AGAINST CHRONIC HYPOXIA
Autore:
HOCHACHKA PW; CLARK CM; BROWN WD; STANLEY C; STONE CK; NICKLES RJ; ZHU GG; ALIEN PS; HOLDEN JE;
Indirizzi:
UNIV BRITISH COLUMBIA,DEPT ZOOL VANCOUVER V6T 1Z4 BC CANADA UNIV BRITISH COLUMBIA,DEPT PSYCHIAT VANCOUVER BC CANADA UNIV WISCONSIN,DEPT MED MADISON WI 00000 UNIV WISCONSIN,DEPT MED PHYS MADISON WI 53706 UNIV ALBERTA,DEPT APPL PHYS MED EDMONTON AB CANADA
Titolo Testata:
Journal of cerebral blood flow and metabolism
fascicolo: 4, volume: 14, anno: 1994,
pagine: 671 - 679
SICI:
0271-678X(1994)14:4<671:TBAH-H>2.0.ZU;2-2
Fonte:
ISI
Lingua:
ENG
Soggetto:
TURTLE BRAIN; GLUCOSE-UTILIZATION; ANDEAN NATIVES; METABOLISM; RAT; ANOXIA; SPECTROSCOPY; DEPENDENCE; ADAPTATION; GLUTAMATE;
Keywords:
BRAIN [F-18] DEOXYGLUCOSE; BRAIN HYPOXIA ADAPTATION; BRAIN GLUCOSE METABOLISM;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Science Citation Index Expanded
Science Citation Index Expanded
Citazioni:
41
Recensione:
Indirizzi per estratti:
Citazione:
P.W. Hochachka et al., "THE BRAIN AT HIGH-ALTITUDE - HYPOMETABOLISM AS A DEFENSE AGAINST CHRONIC HYPOXIA", Journal of cerebral blood flow and metabolism, 14(4), 1994, pp. 671-679

Abstract

The brain of hypoxia-tolerant vertebrates is known to survive extremelimitations of oxygen in part because of very low rates of energy production and utilization. To assess if similar adaptations may be involved in humans during hypoxia adaptation over generational time, volunteer Quechua natives, indigenous to the high Andes between about 3,700 and 4,900 m altitude, served as subjects in positron emission tomographic measurements of brain regional glucose metabolic rates. Two metabolic states were analyzed: (a) the presumed normal (high altitude-adapted) state monitored as soon as possible after leaving the Andes and (b) the deacclimated state monitored after 3 weeks at low altitudes. Proton nuclear magnetic resonance spectroscopy studies of the Quechua brain found normal spectra, with no indication of any unusual lactate accumulation; in contrast, in hypoxia-tolerant species, a relatively large fraction of the glucose taken up by the brain is released as lactate. Positron emission tomographic measurements of [F-18]2-deoxy-2-fluoro-D-glucose (FDG) uptake rates, quantified in 26 regions of the brain, indicated systematically lower region-by-region glucose metabolic rates in Quechuas than in lowlanders. The metabolic reductions were least pronounced in primitive brain structures (e.g., cerebellum) and most pronounced in regions classically associated with higher cortical functions (e.g., frontal cortex). These differences between Quechuas with lifetime exposure to hypobaric hypoxia and lowlanders, which seem to beexpressed to some degree in most brain regions examined, may be the result of a defense adaptation against chronic hypoxia.

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Documento generato il 27/01/20 alle ore 07:24:14