PRIOR STRESS AFFECTS ZIF 268 EXPRESSION AFTER THE RETRIEVAL OF A CONTEXTUAL FEAR MEMORY.

ESPEJO PJ; MALDONADO NM; BUSTOS SG; MOLINA VA

Huerta Grande, Córdoba

Congreso; XXVIII Congreso Anual de la Sociedad Argentina de Investigación en Neurociencias; 2013

Sociedad Argentina de Investigación en Neurociencias

It is well known that a fully consolidated memory can enter into a labile state after retrieval, requiring an additional restabilization process known as reconsolidation. However, there are boundary conditions that limit the occurrence of the labilization/reconsolidation process, for instance, learning strength and memory age, among other factors. Previous studies in our laboratory have shown that a stressful experience prior to a contextual fear conditioning procedure generates a memory that is resistant to the disruptive effect of Midazolam (MDZ) on reconsolidation. The goal of this study was to evaluate the influence of a previous stress experience on the expression of the transcription factor zif 268 in the basolateral amygdala (BLA) after the retrieval of a fear memory. We observed that 90 minutes after reactivation, zif 268 is enhanced in BLA in unstressed animals. In contrast, this increase was not evident in animals that were stressed before fear conditioning. No differences were observed in non reactivated rats. This preliminary result indicates that such molecular event suggested to be involved in the labilization/reconsolidation process is absent in stressed rats. This evidence agrees with the lack of interference on fear memory reconsolidation following MDZ administration in stressed animals. Finally, we propose that the occurrence of a negative emotional state at the moment of learning limits the subsequent emergence of the labilization/reconsolidation process.