Barosensitive neurons in the rat tractus solitarius and paratrigeminal nucleus: a new model for medullary, cardiovascular reflex regulation

Barosensitive neurons in the rat tractus solitarius and paratrigeminal nucleus: a new model for medullary, cardiovascular reflex regulation

Author Balan Junior, Antonio Autor UNIFESP Google Scholar
Caous, Cristofer Andre Autor UNIFESP Google Scholar
Yu, Yun Guo Autor UNIFESP Google Scholar
Lindsey, Charles Julian Autor UNIFESP Google Scholar
Institution Universidade Federal de São Paulo (UNIFESP)
Abstract The nucleus of the solitary tract (NTS), a termination site for primary afferent fibers from baroreceptors and other peripheral cardiovascular receptors, contains blood pressure-sensitive neurons, some of which have rhythmic activity locked to the cardiac cycle, making them key components of the central pathway for cardiovascular regulation. the paratrigeminal nucleus (Pa5), a small collection of medullary neurons in the dorsal lateral spinal trigeminal tract, like the NTS, receives primary somatosensory inputs of glossopharyngeal, vagal, and other nerves. Recent studies show that the Pa5 has efferent connections to the rostroventrolateral reticular nucleus (RVL), NTS, and ambiguus nucleus, suggesting that its structure may play a role in the baroreceptor reflex modulation. in the present study, simultaneous recording from multiple single neurons in freely behaving rats challenged with i.v. phenylephrine administration, showed that 83% of NTS units and 72% of Pa5 units were baroreceptor sensitive. Whereas most of the baroreceptor-sensitive NTS and Pa5 neurons (86 and 61%, respectively) increased firing rate during the ascending phase of the pressor response, about 16% of Pa5 and NTS baroreceptor-sensitive neurons had a decreased firing rate. On one hand, the decrease in firing rate occurred during the ascending phase of the pressor response, indicating sensitivity to rapid changes in arterial pressure. On the other hand, the increases in neuron activity in the Pa5 or NTS occurred during the entire pressor response to phenylephrine. Cross-correlational analysis showed that 71% of Pa5 and 93% of NTS baroreceptor-activated neurons possessed phasic discharge patterns locked to the cardiac cycle. These findings suggest that the Pa5, like the NTS, acts as a terminal for primary afferents in the medullary-baroreflex or cardiorespiratory-reflex pathways.
Keywords cardiovascular reflexes
baroreflex response
arterial blood pressure
multiple single unit recording
Language English
Date 2004-07-01
Published in Canadian Journal of Physiology and Pharmacology. Ottawa: Natl Research Council Canada, v. 82, n. 7, p. 474-484, 2004.
ISSN 0008-4212 (Sherpa/Romeo, impact factor)
Publisher Natl Research Council Canada
Extent 474-484
Origin http://dx.doi.org/10.1139/Y04-054
Access rights Open access Open Access
Type Article
Web of Science ID WOS:000224091600006
URI http://repositorio.unifesp.br/handle/11600/27807

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