RESUMEN
In the present paper, we have evaluated the participation of 5-HT(3) and 5-HT(2C) receptors in the central amygdala (CeA) in the regulation of water and salt intake in sodium-depleted rats. m-CPBG-induced pharmacological activation of 5-HT(3) receptors located in the CeA resulted in a significant reduction in salt intake in sodium-depleted rats. This antinatriorexic effect of m-CPBG was reverted by pretreatment with the selective 5-HT(3) receptor antagonist ondansetron. The injection of ondansetron alone into the CeA had no effect on sodium-depleted and normonatremic rats. Conversely, pharmacological stimulation of 5-HT(2C) receptors located in the central amygdala by the selective 5-HT(2C) receptor agonist m-CPP failed to modify salt intake in sodium-depleted rats. Additionally, the administration of a selective 5-HT(2C) receptor blocker, SDZ SER 082, failed to modify salt intake in rats submitted to sodium depletion. These results lead to the conclusion that the pharmacological activation of 5-HT(3) receptors located within the CeA inhibits salt intake in sodium-depleted rats and that 5-HT(2C) receptors located within the CeA appear to be dissociated from the salt intake control mechanisms operating in the central amygdala.
Asunto(s)
Amígdala del Cerebelo/metabolismo , Regulación del Apetito/fisiología , Receptor de Serotonina 5-HT2C/metabolismo , Receptores de Serotonina 5-HT3/metabolismo , Sodio en la Dieta/metabolismo , Amígdala del Cerebelo/efectos de los fármacos , Animales , Regulación del Apetito/efectos de los fármacos , Ingestión de Líquidos/efectos de los fármacos , Ingestión de Líquidos/fisiología , Masculino , Microinyecciones , Ratas , Ratas Wistar , Receptor de Serotonina 5-HT2C/efectos de los fármacos , Receptores de Serotonina 5-HT3/efectos de los fármacos , Serotoninérgicos/farmacologíaRESUMEN
The relative contributions of feedforward and recurrent connectivity to the direction-selective responses of cells in layer IVB of primary visual cortex are currently the subject of debate in the neuroscience community. Recently, biophysically detailed simulations have shown that realistic direction-selective responses can be achieved via recurrent cortical interactions between cells with nondirection-selective feedforward input (Suarez et al., 1995; Maex & Orban, 1996). Unfortunately these models, while desirable for detailed comparison with biology, are complex and thus difficult to analyze mathematically. In this article, a relatively simple cortical dynamical model is used to analyze the emergence of direction-selective responses via recurrent interactions. A comparison between a model based on our analysis and physiological data is presented. The approach also allows analysis of the recurrently propagated signal, revealing the predictive nature of the implementation.