title: Mapping brain Fos immunoreactivity in response to water deprivation and partial rehydration: Influence of sodium intake.
abstract: Water deprivation (WD) followed by water intake to satiety, produces satiation of thirst and partial rehydration (PR). Thus, WD-PR is a natural method to differentiate thirst from sodium appetite. WD-PR also produces Fos immunoreactivity (Fos-ir) in interconnected areas of a brain circuit postulated to subserve sodium appetite. In the present work, we evaluated the effect of sodium intake on Fos-ir produced by WD-PR in brain areas operationally defined according to the literature as either facilitatory or inhibitory to sodium intake. Isotonic NaCl was available for ingestion in a sodium appetite test performed immediately after a single episode of WD-PR. Sodium intake decreased Fos-ir in facilitatory areas such as the lamina terminalis (particularly subfornical organ and median preoptic nucleus), central amygdala and hypothalamic parvocellular paraventricular nucleus in the forebrain. Sodium intake also decreased Fos-ir in inhibitory areas such as the area postrema, lateral parabrachial nucleus and nucleus of the solitary tract in the hindbrain. In contrast, sodium intake further increased Fos-ir that was activated by water deprivation in the dorsal raphe nucleus, another inhibitory area localized in the hindbrain. WD-PR increased Fos-ir in the core and shell of the nucleus accumbens. Sodium intake reduced Fos-ir in both parts of the accumbens. In summary, sodium intake following WD-PR reduced Fos-ir in most facilitatory and inhibitory areas, but increased Fos-ir in another inhibitory area. It also reduced Fos-ir in a reward area (accumbens). The results suggest a functional link between sodium intake and the activity of the hindbrain-forebrain circuitry subserving reward and sodium appetite in response to water deprivation.
authors: Instituto de Investigación Médica Mercedes y Martín Ferreyra (INIMEC-CONICET-Universidad Nacional de Córdoba), Córdoba, Argentina.
authors: Carolina
authors: C
authors: Dalmasso
authors: Department of Physiology, School of Medicine, University of São Paulo - USP, Ribeirão Preto, São Paulo, Brazil.
authors: José
authors: J
authors: Antunes-Rodrigues
authors: Instituto de Investigación Médica Mercedes y Martín Ferreyra (INIMEC-CONICET-Universidad Nacional de Córdoba), Córdoba, Argentina.
authors: Laura
authors: L
authors: Vivas
authors: Department of Physiology and Pathology, School of Dentistry, Universidade Estadual Paulista - UNESP, Araraquara, São Paulo, Brazil. Electronic address: lucajr@foar.unesp.br.
authors: Laurival A
authors: LA
authors: De Luca
mesh_terms: D000818:Animals; D001066:Appetite / Q000502:physiology; D001921:Brain / Q000378:metabolism* / Q000473:pathology; D003681:Dehydration / Q000378:metabolism* / Q000473:pathology / Q000628:therapy*; D004326:Drinking / Q000502:physiology; D005440:Fluid Therapy / Q000379:methods; D008297:Male; D010784:Photomicrography; D016760:Proto-Oncogene Proteins c-fos / Q000378:metabolism*; D017208:Rats, Wistar; D012201:Reward; D017673:Sodium Chloride, Dietary / Q000008:administration & dosage; D013894:Thirst / Q000502:physiology; D014868:Water Deprivation / Q000502:physiology*
chemical_list: D016760:Proto-Oncogene Proteins c-fos; D017673:Sodium Chloride, Dietary
keywords: Angiotensin II; Reward; Satiety; Sodium appetite; Thirst; Water intake