Abstract
Environmental enrichment (EE) is an experimental model that enhances the opportunity of animals to interact with sensory, motor, and social stimuli compared to the standard conditions. Among the benefits of EE are the improvements in learning and memory, as well as reduction in stress-induced behaviors, including anxiety. Overall, the most conclusive findings on the latter issue show a casual relationship between stress-induced changes in the hippocampus and amygdala and a long-lasting anxiety symptoms emergence. In this regard, EE has gained attention for promoting or restoring the normal adult hippocampal neurogenesis process, as well as by modulating the systemic release of glucocorticoid hormones. However, the relationship among stress, anxiety and the mechanisms through EE exerts its protective role remains inconclusive, especially considering the immediate effects exerted by acute stress on animal behavior. The present study aimed to check whether EE influences the processing of the stressor stimulus in order to modify the course of behavioral response in rats, and which biomolecular changes would be related to this process. For this purpose, we kept the animals in EE (14 days) prior to restraint stress (1h) and, just after the stressor stimulus, we measured the anxiety-like behavior and possible changes in intracellular pathways in these animals. Briefly, we found that EE was able to prevent the emergence of anxiety-like symptoms triggered immediately after stress and that this effect may be related to the modulation, in the basolateral amygdala, nuclear GR signaling, ERK (a MAPK protein) and CREB activity, as well as to changes in the expression of BDNF receptor. (AU)
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