Lateral Parabrachial Afferent Areas and Serotonin Mechanisms Activated by Volume Expansion

Author(s)

Margatho, Lisandra Oliveira ^[1] ; Godino, Andrea ^[2] ; Tenorio Oliveira, Fabiola Raquel ^[3] ; Vivas, Laura ^[2] ; Antunes-Rodrigues, Jose ^[1]

Affiliation

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

^[2] INIMEC CONICET, Inst Invest Med Mercedes & Martin Ferreyra, RA-5000 Cordoba - Argentina

^[3] Fed Univ Para, Dept Physiol, BR-66059 Belem, Para - Brazil

• Document type: Journal article
• Source: Journal of Neuroscience Research; v. 86, n. 16, p. 3613-3621, DEC 2008.
• Web of Science Citations: 13

Abstract

Recent evidence has shown that the serotonergic mechanism of the lateral parabrachial nucleus (LPBN) participates in the regulation of renal and hormonal responses to isotonic blood volume expansion (BVE). We investigated the BVE-induced Fos activation along forebrain and hindbrain nuclei and particularly within the serotonergic clusters of the raphe system that directly project to the LPBN. We also examined whether there are changes in the concentration of serotonin (5HT) within the raphe nucleus in response to the same stimulus. With this purpose, we analyzed the cells doubly labeled for Fos and Fluorogold (FG) following BVE (NaCl 0.15 M, 2 ml/100 g b.w., 1 min) 7 days after FG injection into the LPBN. Compared with the control group, blood volume-expanded rats showed a significant greater number of Fos-FG double-labeled cells along the nucleus of the solitary tract, locus coeruleus, hypothalamic paraventricular nucleus, central extended amygdala complex, and dorsal raphe nucleus (DRN) cells. Our study also showed an increase in the number of serotonergic DRN neurons activated in response to isotonic BVE. We also observed decreased levels of 5HT and its metabolite 5-hydroxyindoleacetic acid (measured by high-pressure liquid chromatography) within the raphe nucleus 15 min after BVE. Given our previous evidence on the role of the serotonergic system in the LPBN after BVE, the present morphofunctional findings suggest the existence of a key pathway (DRN-LPBN) that may control BVE response through the modulation of 5HT release. (c) 2008 Wiley-Liss, Inc. (AU)

• FAPESP's process: 03/00327-8 - Integrative studies of the body fluid homeostasis: physiological and molecular aspects of the neuroendocrine control and clinical and experimental evaluation
• Grantee: José Antunes Rodrigues
• Support Opportunities: Research Projects - Thematic Grants