Differential cardiorespiratory control elicited by activation of ventral medullary sites in mice.
J Appl Physiol (1985)
; 89(2): 437-44, 2000 Aug.
Article
em En
| MEDLINE
| ID: mdl-10926624
We studied the respiratory and blood pressure responses to chemical stimulation of two regions of the ventral brainstem in mice: the rostral and caudal ventrolateral medulla (RVLM and CVLM, respectively). Stimulation of the RVLM by microinjections of the excitatory amino acid L-glutamate induced increases in diaphragm activity and breathing frequency, elevation of blood pressure (BP), and a slight increase in heart rate (HR). However, activation of the CVLM induced a decrease in breathing frequency, mainly due to prolongation of expiratory time (TE), and hypotension associated with a slight slowing of HR. Because adrenergic mechanisms are known to participate in the control of respiratory timing, we examined the role of alpha(2)-adrenergic receptors in the RVLM region in mediating these inhibitory effects. The findings demonstrated that blockade of the alpha(2)-adrenergic receptors within the RVLM by prior microinjection of SKF-86466 (an alpha(2)-adrenergic receptor blocker) significantly reduced changes in TE induced by CVLM stimulation but had little effect on BP responses. These results indicate that, in mice, activation of the RVLM increases respiratory drive associated with an elevation of BP, but stimulation of CVLM induces prolongation of TE via an alpha(2)-adrenergic signal transduction pathway.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Fenômenos Fisiológicos Respiratórios
/
Bulbo
/
Fenômenos Fisiológicos Cardiovasculares
Limite:
Animals
Idioma:
En
Revista:
J Appl Physiol (1985)
Assunto da revista:
FISIOLOGIA
Ano de publicação:
2000
Tipo de documento:
Article
País de afiliação:
Brasil
País de publicação:
Estados Unidos