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Utilize este identificador para citar ou criar um link para este item: http://acervodigital.unesp.br/handle/11449/125705
Título: 
Short-term sustained hypoxia induces changes in the coupling of sympathetic and respiratory activities in rats
Autor(es): 
Instituição: 
  • Universidade de São Paulo (USP)
  • Universidade Estadual Paulista (UNESP)
ISSN: 
0022-3751
Financiador: 
  • Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
  • Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
Número do financiamento: 
  • FAPESP: 2006/51159-6
  • FAPESP: 2009/50113-0
  • CNPq: 502098/2008-2
  • CNPq: 301147/2008-6
Resumo: 
Individuals experiencing sustained hypoxia (SH) exhibit adjustments in the respiratory and autonomic functions by neural mechanisms not yet elucidated. In the present study we evaluated the central mechanisms underpinning the SH-induced changes in the respiratory pattern and their impact on the sympathetic outflow. Using a decerebrated arterially perfused in situ preparation, we verified that juvenile rats exposed to SH (10% O2) for 24 h presented an active expiratory pattern, with increased abdominal, hypoglossal and vagal activities during late-expiration (late-E). SH also enhanced the activity of augmenting-expiratory neurones and depressed the activity of post-inspiratory neurones of the Botzinger complex (B ¨ otC) ¨ by mechanisms not related to changes in their intrinsic electrophysiological properties. SH rats exhibited high thoracic sympathetic activity and arterial pressure levels associated with an augmented firing frequency of pre-sympathetic neurones of the rostral ventrolateral medulla (RVLM) during the late-E phase. The antagonism of ionotropic glutamatergic receptors in the BotC/RVLM abolished the late-E bursts in expiratory and sympathetic outputs of SH rats, ¨ indicating that glutamatergic inputs to the BotC/RVLM are essential for the changes in the ¨ expiratory and sympathetic coupling observed in SH rats. We also observed that the usually silent late-E neurones of the retrotrapezoid nucleus/parafacial respiratory group became active in SH rats, suggesting that this neuronal population may provide the excitatory drive essential to the emergence of active expiration and sympathetic overactivity. We conclude that short-term SH induces the activation of medullary expiratory neurones, which affects the pattern of expiratory motor activity and its coupling with sympathetic activity.
Data de publicação: 
2014
Citação: 
Journal of Physiology, v. 592, n. 9, p. 2013-2033, 2014.
Duração: 
2013-2033
Fonte: 
http://onlinelibrary.wiley.com/doi/10.1113/jphysiol.2013.262212/abstract?systemMessage=Wiley+Online+Library+will+have+intermittent+access+on+8th+August+2015+from+10%3A00-16%3A00+BST+%2F+05%3A00-11%3A00+EDT+%2F+17%3A00-23%3A00+SGT+for+essential+maintenance.++Apologies+for+the+inconvenience.
Endereço permanente: 
Direitos de acesso: 
Acesso aberto
Tipo: 
outro
Fonte completa:
http://repositorio.unesp.br/handle/11449/125705
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