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Titolo:
Effects of a three-day head-down tilt on renal and hormonal responses to acute volume expansion
Autore:
Mauran, P; Sediame, S; Pavy-Le Traon, A; Maillet, A; Carayon, A; Barthelemy, C; Weerts, G; Guell, A; Adnot, S;
Indirizzi:
Hop Henri Mondor, Serv Physiol & Explorat Fonct, Lab Explorat Vasc & Metab, F-94010 Creteil, France Hop Henri Mondor Creteil France F-94010 & Metab, F-94010 Creteil, France INSERM U492, F-94010 Creteil, France INSERM U492 Creteil France F-94010INSERM U492, F-94010 Creteil, France Amer Mem Hosp, Fac Med Reims, Dept Physiol, F-51092 Reims, France Amer MemHosp Reims France F-51092 , Dept Physiol, F-51092 Reims, France CHU Rangueil, Inst Med & Physiol Spatiales, MEDES, F-31403 Toulouse 4, France CHU Rangueil Toulouse France 4 tiales, MEDES, F-31403 Toulouse 4, France Ctr Natl Etud Spatiales, F-75039 Paris 01, France Ctr Natl Etud SpatialesParis France 01 tiales, F-75039 Paris 01, France
Titolo Testata:
AMERICAN JOURNAL OF PHYSIOLOGY-REGULATORY INTEGRATIVE AND COMPARATIVE PHYSIOLOGY
fascicolo: 5, volume: 277, anno: 1999,
pagine: R1444 - R1452
SICI:
0363-6119(199911)277:5<R1444:EOATHT>2.0.ZU;2-Q
Fonte:
ISI
Lingua:
ENG
Soggetto:
ATRIAL-NATRIURETIC-FACTOR; ENDOCRINE RESPONSES; NEURAL CONTROL; HUMANS; WEIGHTLESSNESS; HEMODYNAMICS; MICROGRAVITY; -6-DEGREES; INFUSION; POSTURE;
Keywords:
microgravity; body fluids; renal function; hydromineral balance; fluid-regulating hormones; central blood volume;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Life Sciences
Citazioni:
24
Recensione:
Indirizzi per estratti:
Indirizzo: Adnot, S Hop Henri Mondor, Lab Physiol & Explorat Fonct, F-94010 Creteil, France Hop Henri Mondor Creteil France F-94010 F-94010 Creteil, France
Citazione:
P. Mauran et al., "Effects of a three-day head-down tilt on renal and hormonal responses to acute volume expansion", AM J P-REG, 277(5), 1999, pp. R1444-R1452

Abstract

To clarify whether exposure to 6 degrees head-down tilt (HDT) leads to alterations in body fluid volumes and responses to a saline load similar to those observed during space flight we investigated eight healthy subjects during a 4-day, 6 degrees HDT and during a time-control ambulatory period withcross-over. Compared with the ambulatory period, HDT was associated with greater urinary excretion of wader and sodium (UV, UNaV) from 0 to 12h(cumulated UV 1,781 +/- 154 vs. 1,383 +/- 170 ml, P < 0.05; cumulated UNaV 156 +/- 14 vs. 117 +/- 9 mmol, P < 0.05), and with higher plasma atrial natriuretic factor (ANF) at 4 h. Hemoglobin and hematocrit increased over the first 24 h, and blood and plasma volumes were decreased after 48 h of HDT (P < 0.05). Plasma renin activity (PRA) and aldosterone did not differ between thetwo groups. With prolongation of HDT, UV and UNaV returned close to baseline values. On the fourth HDT day, a a 30-min infusion of 20 ml/kg isotonic saline was performed, while a large oral water load maintained a high urineoutput. The ambulatory period experiment was done with the subjects in theacute supine posture. Sodium excreted within 4 h of loading was 123 +/- 8 mmol during HDT vs. 168 +/- 16 mmol during the ambulatory period (P < 0.05). The increase in plasma ANF and decrease in PRA were greater during KDT than during the ambulatory period (ANF 30 +/- 5 vs. 13 +/- 4 P < 0.05). Our data suggest that after a 3-day HDT period, thoracic volume receptor loadingreturns to the level seen in the upright position, leading to blunted responses to volume expansion, compared with acute supine control.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 26/01/20 alle ore 22:45:03