INTERMITTENT ACTIVATION OF PERIPHERAL CHEMORECEPTORS IN AWAKE RATS INDUCES Fos EXPRESSION IN ROSTRAL VENTROLATERAL MEDULLA-PROJECTING NEURONS IN THE PARAVENTRICULAR NUCLEUS OF THE HYPOTHALAMUS

Autor(es)

Cruz, J. C. ^[1] ; Bonagamba, L. G. H. ^[1] ; Machado, B. H. ^[1] ; Biancardi, V. C. ^[2] ; Stern, J. E. ^[2]

Afiliação do(s) autor(es)

^[1] Univ Sao Paulo, Sch Med, Dept Physiol, BR-14049900 Ribeirao Preto, SP - Brazil

^[2] Med Coll Georgia, Dept Physiol, Augusta, GA 30912 - USA

• Tipo de documento: Artigo Científico
• Fonte: Neuroscience; v. 157, n. 2, p. 463-472, NOV 19 2008.
• Citações Web of Science: 30

Resumo

Despite the well-established sympathoexcitation evoked by chemoreflex activation, the specific sub-regions of the CNS underlying such sympathetic responses remain to be fully characterized. In the present study we examined the effects of intermittent chemoreflex activation in awake rats on Fos-immunoreactivity (Fos-ir) in various subnuclei of the paraventricular nucleus of the hypothalamus (PVN), as well as in identified neurosecretory preautonomic PVN neurons. In response to intermittent chemoreflex activation, a significant increase in the number of Fos-ir cells was found in autonomic-related PVN subnuclei, including the posterior parvocellular, ventromedial parvocellular and dorsal-cap, but not in the neurosecretory magnocellular-containing lateral magnocellular subnucleus. No changes in Fos-ir following chemoreflex activation were observed in the anterior PVN subnucleus. Experiments combining Fos immunohistochemistry and neuronal tract tracing techniques showed a significant increase in Fos-ir in rostral ventrolateral medulla (RVLM)-projecting (PVN-RVLM), but not in nucleus of solitarii tract (NTS)-projecting PVN neurons. In summary, our results support the involvement of the PVN in the central neuronal circuitry activated in response to chemoreflex activation, and indicate that PVN-RVLM neurons constitute a neuronal substrate contributing to the sympathoexcitatory component of the chemoreflex. Published by Elsevier Ltd on behalf of IBRO. (AU)

• Processo FAPESP: 04/03285-7 - Mecanismos centrais da excitação simpática promovida pela hipóxia
• Beneficiário: Benedito Honorio Machado
• Linha de fomento: Auxílio à Pesquisa - Temático
• Processo FAPESP: 01/01252-6 - Estudo imunocitoquímico de receptores de aminoácidos excitatórios e de receptores purinérgicos em neurônios do núcleo do trato solitário e do núcleo paraventricular do hipotálamo envolvidos com o controle autonômico da função cardiovascular
• Beneficiário: Benedito Honorio Machado
• Linha de fomento: Auxílio à Pesquisa - Regular