title: Role of the 5-HT(1A) somatodendritic autoreceptor in the dorsal raphe nucleus on salt satiety signaling in rats.
abstract: We investigated the possible role of 5-HT(1A) somatodendritic autoreceptors in the dorsal raphe nucleus (DRN) on salt intake response during basal conditions and following natriorexigenic challenge aroused by sodium depletion in rats. Acute systemic administration (76-1520 nmol/kg s.c.) of 8-OH-DPAT, a selective 5-HT(1A) somatodendritic autoreceptor agonist, induced a clear and dose-dependent preference for salt intake through free choice between water and 0.3 M NaCl simultaneously offered under basal conditions. Acute intra-DRN microinjection (7.5 nmol/rat) of 8-OH-DPAT significantly mimicked the acute systemic protocol in sodium-replete rats. Interestingly, microinjection of 8-OH-DPAT into the DRN raised an additional long-lasting increase of 0.3 M NaCl intake in sodium-depleted rats despite a high volume ingested 30 min after central injection. Conversely, chronic systemic treatment (1520 nmol/kg s.c.) with 8-OH-DPAT for 2 and 3 weeks or repeated intra-DRN microinjection (7.5 nmol/rat) evoked a significant long-term decrease in 0.3 M NaCl intake in sodium-depleted rats given only water and a sodium-deficient diet over the course of 24 h after furosemide injection. These results show a clear-cut involvement of the DRN 5-HT(1A) somatodendritic autoreceptors in sodium satiety signaling under basal conditions and during the consummatory phase of salt intake in sodium-depleted rats.
authors.affiliation: Department of Physiologic Sciences, Institute de Biology, Federal Rural University of Rio de Janeiro, BR465, Km07 23890-000, Seropédica, RJ, Brazil.
authors.forename: Fabricia Viana
authors.initials: FV
authors.lastname: Fonseca
authors.forename: André Souza
authors.initials: AS
authors.lastname: Mecawi
authors.forename: Iracema Gomes
authors.initials: IG
authors.lastname: Araujo
authors.forename: Gislaine
authors.initials: G
authors.lastname: Almeida-Pereira
authors.forename: Ana Paula
authors.initials: AP
authors.lastname: Magalhães-Nunes
authors.forename: Daniel
authors.initials: D
authors.lastname: Badauê-Passos
authors.forename: Luís Carlos
authors.initials: LC
authors.lastname: Reis