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Titolo:
Catecholamine responses to alpha-adrenergic blockade during exercise in women acutely exposed to altitude
Autore:
Mazzeo, RS; Carroll, JD; Butterfield, GE; Braun, B; Rock, PB; Wolfel, EE; Zamudio, S; Moore, LG;
Indirizzi:
Univ Colorado, Dept Kinesiol & Appl Physiol, Boulder, CO 80309 USA Univ Colorado Boulder CO USA 80309 & Appl Physiol, Boulder, CO 80309 USA Palo Alto Vet Affairs Hlth Care Syst, Palo Alto, CA 94304 USA Palo Alto Vet Affairs Hlth Care Syst Palo Alto CA USA 94304 CA 94304 USA USA, Environm Med Res Inst, Natick, MA 01760 USA USA Natick MA USA 01760USA, Environm Med Res Inst, Natick, MA 01760 USA Univ Colorado, Hlth Sci Ctr, Denver, CO 80220 USA Univ Colorado Denver COUSA 80220 ado, Hlth Sci Ctr, Denver, CO 80220 USA
Titolo Testata:
JOURNAL OF APPLIED PHYSIOLOGY
fascicolo: 1, volume: 90, anno: 2001,
pagine: 121 - 126
SICI:
8750-7587(200101)90:1<121:CRTABD>2.0.ZU;2-O
Fonte:
ISI
Lingua:
ENG
Soggetto:
MUSCLE SYMPATHETIC ACTIVITY; SUBMAXIMAL EXERCISE; SYMPATHOADRENAL RESPONSES; ADRENOCEPTOR BLOCKADE; GENDER DIFFERENCES; HUMANS; HYPOXEMIA; HYPOXIA; ACCLIMATIZATION; NOREPINEPHRINE;
Keywords:
epinephrine; norepinephrine; sympathetics; hypoxia;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Life Sciences
Citazioni:
27
Recensione:
Indirizzi per estratti:
Indirizzo: Mazzeo, RS Univ Colorado, Dept Kinesiol, Box 354, Boulder, CO 80309 USA Univ Colorado Box 354 Boulder CO USA 80309 oulder, CO 80309 USA
Citazione:
R.S. Mazzeo et al., "Catecholamine responses to alpha-adrenergic blockade during exercise in women acutely exposed to altitude", J APP PHYSL, 90(1), 2001, pp. 121-126

Abstract

We have previously documented the importance of the sympathetic nervous system in acclimatizing to high altitude in men. The purpose of this investigation was to determine the extent to which alpha -adrenergic blockade affects the sympathoadrenal responses to exercise during acute high-altitude exposure in women. Twelve eumenorrheic women (24.7 +/- 1.3 yr, 70.6 +/- 2.6 kg) were studied at sea level and on day 2 of high-altitude exposure (4,300-mhypobaric chamber) in either their follicular or luteal phase. Subjects performed two graded-exercise tests at sea level (on separate days) on a bicycle ergometer after 3 days of taking either a placebo or an alpha -blocker (3 mg/day prazosin). Subjects also performed two similar exercise tests while at altitude. Effectiveness of blockade was determined by phenylephrine challenge. At sea level, plasma norepinephrine levels during exercise were 48% greater when subjects were alpha -blocked compared with their placebo trial. This difference was only 25% when subjects were studied at altitude. Plasma norepinephrine values were significantly elevated at altitude compared with sea level but to a greater extent for the placebo (up arrow 59%) vs.blocked (up arrow 35%) trial. A more dramatic effect of both altitude (up arrow 104% placebo vs. 95% blocked) and blockade (up arrow 50% sea level vs. 44% altitude) was observed for plasma epinephrine levels during exercise. No phase differences were observed across any condition studied. It was concluded that alpha -adrenergic blockade 1) resulted in a compensatory sympathoadrenal response during exercise at sea level and altitude, and 2) this effect was more pronounced for plasma epinephrine.

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Documento generato il 19/01/20 alle ore 20:38:49