title: Ingestive and locomotor behaviours induced by pharmacological manipulation of <Alpha>-adrenoceptors into the median raphe nucleus.
abstract: The present study evaluated the involvement of α-adrenoceptors of the median raphe nucleus (MRN) in satiated rats, in food and water intake and motor behaviour. Control groups were treated with saline (SAL) or adrenaline (ADR), injected into the MRN seven minutes after injection of the vehicle used to solubilize the antagonists, propylene glycol (PLG) or SAL. Experimental groups were treated with an α-adrenoceptor antagonist, prazosin (α1, 20 or 40 nmol) or yohimbine (α2, 20 or 40 nmol) or phentolamine (non-selective α, 20 or 40 nmol), followed (later) by injection of ADR or SAL. Behaviour was recorded for 30 min. The injection of ADR and the blockade of α1 receptors resulted in hyperphagia whereas blocking α2 or α1 and α2 simultaneously did not change feeding behaviour. Pre-treatment with prazosin, followed by injection of ADR was not able to cause an increase in the amount of food ingested, while the higher dose of the α1 antagonist reduced the latency to start feeding. Pre-treatment with prazosin also caused hyperactivity. However, pre-treatment with phentolamine or yohimbine was able to block ADR-induced feeding. The present study supports the hypothesis that there is a tonic activation of α1-adrenoceptors in the MRN in satiated rats, which activates an inhibitory influence in areas that control food intake. Injection of ADR seems to activate α2 receptors, resulting in a decrease in the availability of endogenous catecholamines, which reduces the release of the signal that inhibits food intake, leading to hyperphagia.
authors.affiliation: Department of Physiological Sciences, Centre of Biological Sciences, Federal University of Santa Catarina (UFSC), 88040-900 Florianopolis, SC, Brazil. Electronic address: bulevone@gmail.com.
authors.forename: Brunno Rocha
authors.initials: BR
authors.lastname: Levone
authors.affiliation: Department of Physiological Sciences, Centre of Biological Sciences, Federal University of Santa Catarina (UFSC), 88040-900 Florianopolis, SC, Brazil. Electronic address: elisa_cella@hotmail.com.
authors.forename: Elisa Caroline
authors.initials: EC
authors.lastname: Cella
authors.affiliation: Department of Physiological Sciences, Centre of Biological Sciences, Federal University of Santa Catarina (UFSC), 88040-900 Florianopolis, SC, Brazil. Electronic address: larissakochen@gmail.com.
authors.forename: Larissa
authors.initials: L
authors.lastname: Kochenborger
authors.affiliation: Department of Physiological Sciences, Centre of Biological Sciences, Federal University of Santa Catarina (UFSC), 88040-900 Florianopolis, SC, Brazil. Electronic address: edu_simao@yahoo.com.br.
authors.forename: Eduardo Simão
authors.initials: ES
authors.lastname: da Silva
authors.affiliation: Department of Physiological Sciences, Centre of Biological Sciences, Federal University of Santa Catarina (UFSC), 88040-900 Florianopolis, SC, Brazil. Electronic address: anapaulataschetto@gmail.com.
authors.forename: Ana Paula Dambros
authors.initials: AP
authors.lastname: Taschetto
authors.affiliation: Department of Morphological Sciences, Centre of Biological Sciences, Federal University of Santa Catarina (UFSC), Florianopolis, SC, Brazil. Electronic address: samirasmansur@hotmail.com.
authors.forename: Samira Schultz
authors.initials: SS
authors.lastname: Mansur
authors.affiliation: Department of Physiological Sciences, Centre of Biological Sciences, Federal University of Santa Catarina (UFSC), 88040-900 Florianopolis, SC, Brazil. Electronic address: mariana.terenzi@ufsc.br.
authors.forename: Mariana Graciela
authors.initials: MG
authors.lastname: Terenzi
authors.affiliation: Department of Physiological Sciences, Centre of Biological Sciences, Federal University of Santa Catarina (UFSC), 88040-900 Florianopolis, SC, Brazil. Electronic address: m.serralvo@ufsc.br.
authors.forename: Moacir Serralvo
authors.initials: MS
authors.lastname: Faria
authors.affiliation: Department of Physiological Sciences, Centre of Biological Sciences, Federal University of Santa Catarina (UFSC), 88040-900 Florianopolis, SC, Brazil. Electronic address: marta@ccb.ufsc.br.
authors.forename: Marta Aparecida
authors.initials: MA
authors.lastname: Paschoalini
mesh_terms: D058668:Adrenergic alpha-1 Receptor Antagonists / Q000494:pharmacology*; D000818:Animals; D004435:Eating / Q000187:drug effects / Q000502:physiology*; D008297:Male; D009043:Motor Activity / Q000187:drug effects / Q000502:physiology*; D011903:Raphe Nuclei / Q000187:drug effects / Q000502:physiology*; D051381:Rats; D017208:Rats, Wistar; D011942:Receptors, Adrenergic, alpha / Q000502:physiology*
chemical_list: D058668:Adrenergic alpha-1 Receptor Antagonists; D011942:Receptors, Adrenergic, alpha
keywords: Alpha-adrenoceptors; Food intake; Median raphe nucleus; Serotonin