RESUMEN
The present study examined the effects of 5-HT1A and 5-HT2C receptor agonists on behavioral satiety sequence (BSS) in rats. The 5-HT1A receptor agonist, 8-OH-DPAT (0.5 microg), and the 5-HT2C receptor agonist, Ro-60-0175 (3.0 microg), were injected into the paraventricular nucleus (PVN) of rats. The animals were maintained on an ad libitum feeding paradigm with access to water and individual sources of protein, carbohydrate, and fat. Intra-PVN administration of each agonist was associated with decreased carbohydrate consumption. The effect was enhanced by the administration of both agonists together. Behavioral analysis indicated that co-administration of 8-OH-DPAT and Ro-60-0175 interrupted the natural BSS with an increase in non-feeding behavior, whereas the 8-OH-DPAT alone promoted early development of the natural BSS. In conclusion, the 5-HT receptor agonists affected serotonergic modulation of feeding behavior in a functionally selective way.
Asunto(s)
8-Hidroxi-2-(di-n-propilamino)tetralin/farmacología , Etilaminas/farmacología , Conducta Alimentaria/efectos de los fármacos , Indoles/farmacología , Agonistas de Receptores de Serotonina/farmacología , Análisis de Varianza , Animales , Conducta Animal/efectos de los fármacos , Interacciones Farmacológicas , Ingestión de Alimentos/efectos de los fármacos , Masculino , Núcleo Hipotalámico Paraventricular/efectos de los fármacos , Ratas , Ratas WistarRESUMEN
El objetivo de la presente investigación fue evaluar el efecto de la estimulación de los receptores CRH2 del núcleo paraventricular hipotalámico sobre la ingesta de alimento y la expresión de la secuencia de saciedad conductual (SSC) en ratas adrenalectomizadas. Se trabajó con ocho grupos independientes de ratas Wistar, cuatro grupos adrenalectomizados (ADX) y cuatro con falsa cirugía. A todos los sujetos se les implantó una cánula en el núcleo paraventricular hipotalámico, y se les administró uno de cuatro tratamientos: vehículo, urocortina 2 (UCN2, agonista de CRH2), antisauvagina 30 (antagonista de CRH2), y antisauvagina-30 + UCN2 (pretratamiento). La administración de UCN2 redujo la ingesta de hidratos de carbono y de grasas en las ratas ADX, debido a la interrupción de la SSC; mientras que en las ratas con falsa cirugía, la UCN2 solo disminuyó la ingesta de grasas, debido al adelanto de la SSC. El pretratamiento previno los efectos inducidos en las ratas ADX, pero no en las ratas con falsa cirugía. Estos resultados indican que los receptores CRH2 modularon la ingesta y la SSC en las ratas ADX, lo que constituye un aporte importante en la comprensión de la etiología de la anorexia y del patrón conductual asociado a esta.
The objective of this research was to evaluate the effect of stimulation of receptors CRH2 in the paraventricular nucleus of the hypothalamus on food intake and expression of behavioral satiety sequence (BSS) in adrenalectomized rats. Eight independent groups of Wistar rats were utilized; four adrenalectomized groups (ADX) and four were false surgery. All subjects were implanted with a cannula in the paraventricular nucleus of the hypothalamus and were administered with one of the four treatments: vehicle, urocortin-2 (UCN2, CRH2 agonist), antisauvagine-30 (CRH2 antagonist) or antisauvagine-30 + UCN2 (pretreatment). UCN2 administration reduced intake of carbohydrates and fats in ADX rats due to the interruption of the BSS. In rats with false surgery it decreased fat intake due to the advancement of the BSS. Pretreatment prevented the effects induced by UCN2 in ADX rats but not in rats with false surgery. These results suggest that receptors CRH2 modulated intake and BSS in ADX rats, contributing with relevant information for the understanding of the anorexic ethiology and the behavioral pattern associated to it.