El sistema serotoninérgico en un aprendizaje apetitivo

SILVIA PEDETTA; HECTOR MALDONADO

Huerta Grande, Córdoba

Congreso; 1ª Reunión Conjunta en Neurociencias; 2009

Sociedad Argentina de Neurociencias y Taller Argentino de Neurociencias

<!-- /* Style Definitions */ p.MsoNormal, li.MsoNormal, div.MsoNormal {mso-style-parent:""; margin:0cm; margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:12.0pt; font-family:"Times New Roman"; mso-fareast-font-family:"Times New Roman";} @page Section1 {size:612.0pt 792.0pt; margin:70.85pt 3.0cm 70.85pt 3.0cm; mso-header-margin:36.0pt; mso-footer-margin:36.0pt; mso-paper-source:0;} div.Section1 {page:Section1;} --> Serotonin is a biogenic amine that can act as a neurotransmitter, neuromodulator or a neurohormone; and it is involved in a variety of physiological processes.  Its localization in brain areas involved in cognition has made this amine a target for the study of learning and memory. Many reports have been published attributing to serotonin a direct or indirect role in diverse phases of vertebrate memory, and also, but with less frequency, in diverse phases of invertebrate memory. An aversive learning paradigm with the crab Chasmagnathus has been used extensively in our laboratory; it is based on the crab’s escape response elicited by the presentation of a visual danger stimulus, which represents the negative reinforcement. Since this long-term memory results from an association between context and a signal, it is termed context-signal memory (CSM). Our previous results have shown that exogenous administration of serotonin negatively modulates both memory consolidation and reconsolidation of the CSM. Moreover, fluoxetine, an inhibitor of serotonin reuptake, also has an amnesic effect in both memory processes. Recently, a new appetitive learning paradigm was developed, supplying food as a positive reinforcement that becomes associated with the context where it was received. At test session, trained animals perform more exploratory activity than controls when reinstalled in the learning context. The aim of the present work is to characterize the effect of serotonin in this memory paradigm. Preliminary results show that fluoxetine administration has an amnesic effect in this appetitive learning. These results suggest that serotonin may have a detrimental effect on memory irrespective of the learning paradigm used.