Transient cerebral blood flow responses during microgravity.
Life Sci Space Res (Amst)
; 25: 66-71, 2020 May.
Article
em En
| MEDLINE
| ID: mdl-32414494
ABSTRACT
PURPOSE:
A number of studies has well described central cardiovascular changes caused by changing gravity levels as they occur e.g. during parabolic flight. limited data exists describing the effect of microgravity on the cerebrovascular system and brain perfusion.METHODS:
In this study middle cerebral artery velocity (MCAv) of 16 participants was continuously monitored on a second-by-second basis during 15 consecutive parabolas (1G, 1,8G, 0G, 1,8G) using doppler ultrasound. Simultaneously central cardiovascular parameters (heart rate, mean arterial blood pressure, cardiac output) were assessed.RESULTS:
Results revealed an immediate reaction of central cardiovascular parameters to changed gravity levels. In contrast, changes in MCAv only initially were in accordance with a normal cerebral autoregulation. Whereas all of the measured central cardiovascular parameters seemed to have reached a steady state after approximately 8 s of microgravity, MCAv, after an initial decrease with the onset of microgravity, increased again during the second half of the microgravity phase.CONCLUSION:
It is concluded that this increase in MCAv during the second half of the microgravity period reflects a decrease of cerebrovascular resistance caused by a pressure driven increased venous outflow and/or a contraction of precapillary sphincters in order to avoid hyperperfusion of the brain.Palavras-chave
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Resistência Vascular
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Ausência de Peso
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Velocidade do Fluxo Sanguíneo
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Circulação Cerebrovascular
Limite:
Adult
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Female
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Humans
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Male
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Middle aged
Idioma:
En
Revista:
Life Sci Space Res (Amst)
Ano de publicação:
2020
Tipo de documento:
Article
País de afiliação:
Alemanha