Involvement of the parabrachial nucleus in the pressor response to chemoreflex activation in awake rats

Content Provider	Semantic Scholar
Author	Haibara, Andréa Siqueira Tamashiro, Edwin Olivan, Marcelo Vitoriano Bonagamba, Leni G. H. Machado, Benedito H.
Copyright Year	2002
Abstract	Activation of the chemoreflex with potassium cyanide (KCN, 40 microg/rat, i.v.) in awake rats produces pressor and bradycardic responses as well as a tachypneic response. In the present study, we evaluated the involvement of the periaqueductal gray matter (PAG) and the parabrachial nucleus (PBN) in the neural pathways of the cardiovascular responses to chemoreflex activation. The cardiovascular responses to chemoreflex activation were evaluated before and after bilateral microinjection of 2% lidocaine, a local anesthetic, into the PBN or PAG in order to block in a reversible manner the neuronal activity and axonal conduction of fibers of passage in these areas. The data show that the pressor response to chemoreflex activation 3 min after bilateral microinjection of lidocaine into the dorsolateral aspect of the PBN was significantly reduced in comparison to the control response (32 +/- 5 vs. 48 +/- 4 mm Hg, n = 7), with no significant changes in the bradycardic responses. The effect of lidocaine was reversible since the pressor response was back to control levels 15 min after microinjection of this anesthetic. Bilateral microinjections of lidocaine into the dorsolateral (n = 11) or lateral (n = 8) columns of the PAG in distinct groups of rats produced no significant changes in the pressor or bradycardic responses of the chemoreflex. These data indicate that the PBN is part of the neuronal pathways involved in the sympathoexcitatory component of the chemoreflex while the PAG is not.
Starting Page	60
Ending Page	67
Page Count	8
File Format	PDF HTM / HTML
DOI	10.1016/S1566-0702(02)00210-2
PubMed reference number	12462360
Journal	Medline
Volume Number	101
Alternate Webpage(s)	https://api.elsevier.com/content/article/pii/S1566070202002102
Alternate Webpage(s)	https://www.sciencedirect.com/science/article/pii/S1566070202002102?dgcid=api_sd_search-api-endpoint
Alternate Webpage(s)	https://doi.org/10.1016/S1566-0702%2802%2900210-2
Journal	Autonomic Neuroscience
Language	English
Access Restriction	Open
Content Type	Text
Resource Type	Article