INIMEC - CONICET   05467
INSTITUTO DE INVESTIGACION MEDICA MERCEDES Y MARTIN FERREYRA
Unidad Ejecutora - UE
artículos
Título:
Lateral parabrachial nucleus afferent areas and 5HT mechanisms activated by volume expansion.
Autor/es:
MARGATHO-OLIVEIRA, L.; GODINO, A.; TENORIO-OLIVEIRA, F.R., VIVAS, L.; ANTUNES-RODRIGUES
Revista:
JOURNAL OF NEUROSCIENCE RESEARCH
Referencias:
Año: 2008
ISSN:
0360-4012
Resumen:
ABSTRACT Recent evidences showed 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 raphé system that directly project to the LPBN. We also examined if there are changes in the concentration of serotonin (5-HT) within the raphé nucleus in response to the same stimulus. With this purpose we analyzed the cells double-labeled for Fos and Fluorogold (FG) following BVE (NaCl 0.15 M, 2 ml/100 g b.w., 1min) seven days after FG injection into the LPBN. Compared to the control group, blood volume expanded rats showed a significant greater number of Fos-FG doublelabeled cells along the nucleus of the solitary tract, locus coeruleus, hypothalamic paraventricular nucleus, the central extended amygdala complex and the dorsal raphé 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 5-HT and its metabolite 5-hydroxyindoleacetic acid (measured by high pressure liquid chromatography) within the raphé nucleus, 15 minutes after BVE. Taking into account our previous evidence about the role of the serotonergic system into the LPBN after BVE, the present morphofunctional findings suggest the existence of a key pathway (DRN-LPBN) that may control blood volume expansion response through the modulation of 5-HT release.   Key words: Fos and Fluorogold immunoreactivity, dorsal raphé nucleus, lateral parabrachial nucleus, serotonin.