title: Blockade of median raphe nucleus α1-adrenoceptor subtypes increases food intake in rats.
abstract: Previous studies have shown that the blockade of α1-adrenoceptors in the median raphe nucleus (MnR) of free-feeding animals increases food intake. Since there is evidence for the presence of α1A-, α1B- and α1D-adrenoceptors in the MnR of rats, this study investigated the involvement of MnR α1-adrenoceptor subtypes in the control of feeding behavior, looking for possible differences on the role of each α1-adrenoceptor in feeding. Male adult rats weighing 280-300 g with guide cannulae chronically implanted above the MnR were injected with antagonists of α1A- (RS100329, 0, 2, 4 or 20 nmol), α1B- (Rec 15/2615, 0, 2, 4 or 20 nmol) or α1D-adrenoceptor (BMY 7378, 0, 2, 4 or 20 nmol). Subsequently, behavioral evaluation of ingestive and non-ingestive parameters was monitored for 1h and the amount of food and water ingested was assessed for 4h. The highest dose (20 nmol) of RS100329 and BMY 7378 increased food intake, feeding duration and frequency, and decreased the latency to start feeding. During the second hour 2 nmol dose of Rec 15/2615 increased food intake and all doses of BMY 7378 decreased water intake. No behavioral alterations were observed during the fourth hour. The results corroborate previous work from our lab in which we describe the involvement of α1-adrenoceptors of MnR on food intake control. Moreover, we show evidence that α1A- and α1D-adrenoceptors mediate feeding responses to adrenaline injections and that the behavioral modifications are of considerable duration, persisting up to 2h after injection of the antagonists.
authors: Department of Physiological Sciences, Center of Biological Sciences - CCB, Federal University of Santa Catarina (UFSC), 88040-970, Florianópolis, SC, Brazil. Electronic address: edu_simao@yahoo.com.br.
authors: Eduardo Simão
authors: ES
authors: da Silva
authors: Department of Physiological Sciences, Center of Biological Sciences - CCB, Federal University of Santa Catarina (UFSC), 88040-970, Florianópolis, SC, Brazil.
authors: Rafael Appel
authors: RA
authors: Flores
authors: Department of Physiological Sciences, Center of Biological Sciences - CCB, Federal University of Santa Catarina (UFSC), 88040-970, Florianópolis, SC, Brazil.
authors: Elisa Carolina
authors: EC
authors: Cella
authors: Department of Physiological Sciences, Center of Biological Sciences - CCB, Federal University of Santa Catarina (UFSC), 88040-970, Florianópolis, SC, Brazil.
authors: Brunno Rocha
authors: BR
authors: Levone
authors: Department of Physiological Sciences, Center of Biological Sciences - CCB, Federal University of Santa Catarina (UFSC), 88040-970, Florianópolis, SC, Brazil.
authors: Ana Paula
authors: AP
authors: Taschetto
authors: Department of Physiological Sciences, Center of Biological Sciences - CCB, Federal University of Santa Catarina (UFSC), 88040-970, Florianópolis, SC, Brazil.
authors: Larissa
authors: L
authors: Kochenborger
authors: Department of Physiological Sciences, Center of Biological Sciences - CCB, Federal University of Santa Catarina (UFSC), 88040-970, Florianópolis, SC, Brazil.
authors: Mariana Graciela
authors: MG
authors: Terenzi
authors: Department of Physiological Sciences, Center of Biological Sciences - CCB, Federal University of Santa Catarina (UFSC), 88040-970, Florianópolis, SC, Brazil.
authors: Moacir Serralvo
authors: MS
authors: Faria
authors: Department of Physiological Sciences, Center of Biological Sciences - CCB, Federal University of Santa Catarina (UFSC), 88040-970, Florianópolis, SC, Brazil.
authors: Marta Aparecida
authors: MA
authors: Paschoalini
mesh_terms: D058668:Adrenergic alpha-1 Receptor Antagonists / Q000494:pharmacology*; D000818:Animals; D065847:Dorsal Raphe Nucleus / Q000187:drug effects* / Q000378:metabolism; D005247:Feeding Behavior / Q000187:drug effects*; D008297:Male; D051381:Rats; D017208:Rats, Wistar
chemical_list: D058668:Adrenergic alpha-1 Receptor Antagonists
keywords: Food intake; Median raphe nucleus; Rat; α(1)-Adrenoceptor