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Titolo:
Central volume expansion is pivotal for sustained decrease in heart rate during seated to supine posture change
Autore:
Pump, B; Kamo, T; Gabrielsen, A; Bie, P; Christensen, NJ; Norsk, P;
Indirizzi:
Rigshosp, Danish Aerosp Med Ctr Res, DK-2100 Copenhagen, Denmark RigshospCopenhagen Denmark DK-2100 Ctr Res, DK-2100 Copenhagen, Denmark Odense Univ, Dept Physiol, DK-5000 Odense C, Denmark Odense Univ Odense Denmark C iv, Dept Physiol, DK-5000 Odense C, Denmark Herlev Hosp, Dept Internal Med & Endocrinol, DK-2730 Herlev, Denmark Herlev Hosp Herlev Denmark DK-2730 & Endocrinol, DK-2730 Herlev, Denmark St Marianna Univ, Div Neurol, Kawasaki, Kanagawa 2168511, Japan St Marianna Univ Kawasaki Kanagawa Japan 2168511 Kanagawa 2168511, Japan
Titolo Testata:
AMERICAN JOURNAL OF PHYSIOLOGY-HEART AND CIRCULATORY PHYSIOLOGY
fascicolo: 3, volume: 281, anno: 2001,
pagine: H1274 - H1279
SICI:
0363-6135(200109)281:3<H1274:CVEIPF>2.0.ZU;2-D
Fonte:
ISI
Lingua:
ENG
Soggetto:
BODY NEGATIVE-PRESSURE; PLASMA-CATECHOLAMINES; VASOPRESSIN RELEASE; CAROTID BAROREFLEX; HUMANS; REFLEX; STIMULATION; RESPONSES; MUSCLE;
Keywords:
antidiuretic hormone; baroreceptors; blood pressure; lower body negative pressure; neck suction;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Life Sciences
Citazioni:
33
Recensione:
Indirizzi per estratti:
Indirizzo: Pump, B Rigshosp, Danish Aerosp Med Ctr Res, 7805,9 Blegdamsvej, DK-2100 Copenhagen, Denmark Rigshosp 7805,9 Blegdamsvej Copenhagen Denmark DK-2100 n, Denmark
Citazione:
B. Pump et al., "Central volume expansion is pivotal for sustained decrease in heart rate during seated to supine posture change", AM J P-HEAR, 281(3), 2001, pp. H1274-H1279

Abstract

During prolonged, static carotid baroreceptor stimulation by neck suction (NS) in seated humans, heart rate (HR) decreases acutely and thereafter gradually increases. This increase has been explained by carotid baroreceptor adaptation and/or buffering by aortic reflexes. During a posture change from seated to supine (Sup) with similar carotid stimulation, however, the decrease in HR is sustained. To investigate whether this discrepancy is causedby changes in central blood volume, we compared (n = 10 subjects) the effects of 10 min of seated NS (adjusted to simulate carotid stimulation of a posture change), a posture change from seated to Sup, and the same posture change with left atrial (LA) diameter maintained unchanged by lower body negative pressure (Sup + LBNP). During Sup, the prompt decreases in HR and mean arterial pressure (MAP) were sustained. HR decreased similarly within 30 s of NS (65 +/- 2 to 59 +/- 2 beats/min) and Sup + LBNP (65 +/- 2 to 59 +/-2 beats/min) and thereafter gradually increased to values of seated. MAP decreased similarly within 5 min during Sup + LBNP and NS (by 7 +/- 1 to 9 +/- 1 mmHg) and thereafter tended to increase toward values of seated subjects. Arterial pulse pressure was increased the most by Sup, less so by Sup LBNP, and was unchanged by NS. TA diameter was only increased by Sup. In conclusion, static carotid baroreceptor stimulation per se causes the acute (<30 s) decrease in HR during a posture change from seated to Sup, whereas the central volume expansion (increased LA diameter and/or arterial pulse pressure) is pivotal to sustain this decrease. Thus the effects of central volume expansion override adaptation of the carotid baroreceptors and/or buffering of aortic reflexes.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 03/12/20 alle ore 12:08:18