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Titolo:
EFFECTS OF HEAT-STRESS ON VASCULAR CAPACITANCE
Autore:
DESCHAMPS A; MAGDER S;
Indirizzi:
ROYAL VICTORIA HOSP,DIV CRIT CARE,L-305,687 PINE AVE MONTREAL H3A 1A1PQ CANADA ROYAL VICTORIA HOSP,DIV CRIT CARE MONTREAL H3A 1A1 PQ CANADA MCGILL UNIV,MEAKINS CHRISTIE LABS MONTREAL H3A 1A1 PQ CANADA
Titolo Testata:
The American journal of physiology
fascicolo: 5, volume: 266, anno: 1994,
parte:, 2
pagine: 80002122 - 80002129
SICI:
0002-9513(1994)266:5<80002122:EOHOVC>2.0.ZU;2-C
Fonte:
ISI
Lingua:
ENG
Soggetto:
SINUS BARORECEPTOR REFLEX; BLOOD-FLOW; REGIONAL DISTRIBUTION; VOLUME RELATIONSHIPS; SYMPATHETIC ACTIVITY; INDOCYANINE GREEN; ANESTHETIZED DOGS; CARDIAC-OUTPUT; VENOUS RETURN; CAT LIVER;
Keywords:
UNSTRESSED VOLUME; VENOUS COMPLIANCE; VENOUS RESISTANCE; GANGLIONIC BLOCKADE; ALPHA-ADRENERGIC RECEPTOR BLOCKADE; BETA-ADRENERGIC RECEPTOR BLOCKADE;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Citazioni:
37
Recensione:
Indirizzi per estratti:
Citazione:
A. Deschamps e S. Magder, "EFFECTS OF HEAT-STRESS ON VASCULAR CAPACITANCE", The American journal of physiology, 266(5), 1994, pp. 80002122-80002129

Abstract

In dogs and humans, heat stress is associated with an increase in cardiac output that sustains blood flow to heat-dissipating organs. Because cardiac output and venous return are equal in the steady state, thecirculation must also adjust in heat stress to allow the venous return to increase. To analyze these adjustments, we measured blood volumes, unstressed volumes, blood flow distribution, venous compliance, venous resistance, and the time constant of venous drainage of the splanchnic and extrasplanchnic vascular beds in dogs anesthetized with alpha-chloralose at normal and at high core temperatures. We repeated the measurements at high core temperatures with ganglionic blockade, alpha-adrenergic receptor blockade, or beta-adrenergic receptor blockade to determine the efferent neurohumoral pathway. When core temperature was increased from 37.8 +/- 0.2 to 41.9 +/- 0.1 degrees C, total splanchnic blood volume decreased 23% (4.6 +/- 1.4 ml/kg) and splanchnic unstressed volume decreased 38.5%. None of the other determinants of venous return changed. Ganglionic blockade shifted the total and unstressed splanchnic blood volume during heat stress back to normothermic values. However, beta- and alpha-blockade did not affect splanchnic volumes. We conclude that a decrease in splanchnic unstressed volume is an important factor for the increased venous return during heat stress. Although mediated through sympathetic ganglions, this decrease is not abolished by alpha- or beta-receptor blockade.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 28/11/20 alle ore 12:56:49