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(Reference retrieved automatically from Google Scholar through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

Dorsal raphe nuclei integrate allostatic information evoked by depletion-induced sodium ingestion

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Author(s):
Badauê-Passos‚ D. ; Godino‚ A. ; Johnson‚ A.K. ; Vivas‚ L. ; Antunes-Rodrigues‚ J.
Total Authors: 5
Document type: Journal article
Source: Experimental Neurology; v. 206, n. 1, p. 86-94, 2007.
Abstract

Structures of the lamina terminalis (LT) sense and integrate information reflecting the state of body water and sodium content. Output from the LT projects into a neural network that regulates body fluid balance. Serotonin (5-HT) and the dorsal raphe nuclei (DRN) have been implicated in the inhibitory control of salt intake (i.e., sodium appetite). Signals arriving from the LT evoked by fluid depletion-induced sodium ingestion interact with this inhibitory serotonergic system. We investigated the role of neurons along the LT that directly project to the DRN. We analyzed the pattern of immunoreactivity (ir) of LT cells double-labeled for Fos (a marker of neural activity) and Fluorogold (FG; a retrograde tracer) following sodium depletion-induced sodium intake. Seven days after injection of FG into the DRN, sodium appetite was induced by furosemide injection and overnight access to only a low sodium diet (Furo-LSD) and distilled water. Twenty-four hours later, access to 0.3 M NaCl was given to depleted or sham-depleted rats and sodium intake was measured over the following 60 min. Ninety minutes after the termination of the intake test, the animals were perfused and their brains were processed for immunohistochemical detection of Fos and FG. Compared to sham-depleted animals there was a significantly greater number of Fos-/FG-ir double-labeled cells in the subfornical organ, the organum vasculosum of the lamina terminalis and the median preoptic nucleus in rats that ingested NaCl. Projections from the LT cells may contribute to inhibitory mechanisms involving 5-HT neurons in the DRN that limit the intake of sodium and prevent excess volume expansion. (C) 2007 Elsevier Inc. All rights reserved. (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