Differential cardiorespiratory control elicited by activation of ventral medullary sites in mice

Differential cardiorespiratory control elicited by activation of ventral medullary sites in mice

Author Tolentino-Silva, Fatima Rosaria Paulino Autor UNIFESP Google Scholar
Haxhiu, M. A. Google Scholar
Ernsberger, P. Google Scholar
Waldbaum, S. Google Scholar
Dreshaj, I. A. Google Scholar
Institution Case Western Reserve Univ
Universidade Federal de São Paulo (UNIFESP)
Abstract 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.
Keywords respiratory timing
rostral ventrolateral medulla
caudal ventrolateral medulla
L-glutamate
alpha(2)-adrenergic receptors
Language English
Date 2000-08-01
Published in Journal Of Applied Physiology. Bethesda: Amer Physiological Soc, v. 89, n. 2, p. 437-444, 2000.
ISSN 8750-7587 (Sherpa/Romeo, impact factor)
Publisher Amer Physiological Soc
Extent 437-444
Origin http://jap.physiology.org/content/89/2/437
Access rights Closed access
Type Article
Web of Science ID WOS:000088930200009
URI http://repositorio.unifesp.br/11600/44186

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