Event Abstract Back to Event Effects of stress and corticosterone in two post-training periods, on spatial memory consolidation in adult male Wistar rats. Jeimmy M. Cerón1, 2* and Marisol Lamprea Rodríguez1, 2 1 Universidad Nacional de Colombia, Departamento de Psicología, Colombia 2 Universidad Nacional de Colombia, Laboratorio de Neurofisiología Comportamental, Colombia Memory consolidation is the process of gradual stabilization of long-term memory after learning (Alberini & Taubenfeld, 2008). This process involves the activation of intracellular signaling cascades that lead to the reorganization of synaptic proteins. Activation of these signaling pathways can regulate gene expression and protein synthesis (Brivanlou & Darnell, 2002). It is considered that the new proteins synthesized after learning are responsible for the changes in the neural architecture associated with memory consolidation (Mileusnic, 2004). In this sense, it has been shown that consolidation may be interrupted by inhibiting protein synthesis, leading to forgetfulness of the experience (Meeter & Murre, 2004). Although the dominant hypothesis is that memory consolidation requires a single molecular cascade, it has been suggested that multiple sets of synaptic modifications are required to reinforce changes after memory acquisition (Wittenber & Tsien, 2002). Consistently, recent studies have shown that protein synthesis associated with memory consolidation occurs in at least two post-training periods: immediately and 3-6 hours after training (Igaz et al., 2002; Bekinschtein et al., 2007). These memory consolidation periods share some molecular phenomena; however, each period is also associated with events that are different from the other (Igaz et al., 2002). To date, there is a substantial amount of evidence showing that stressful events may facilitate neuronal function and cognition. The term "stress" usually refers to a nonspecific response of the body to stimuli that threaten the physiological/psychological homeostasis (Selye, 1976; Chrousos et al., 1988). The stress response is associated with the activation of two physiological systems: the hypothalamic-pituitary-adrenal (HPA) axis and the sympathetic adrenomedullary (SAM). Glucocorticoids (cortisol in humans and corticosterone in rodents) are steroid hormones secreted by the adrenal glands as a final product of HPA axis activity. These hormones act on specialized receptors located within all body cells; upon activation by ligand binding, these receptors interact with specific regions of DNA, thereby regulating gene expression (Tsigos & Chrousos, 2002). The lipidic nature of glucocorticoids allows them to cross the blood-brain barrier and enter the brain, which may influence cognitive function. The aim of this study was to determine the effects of stress (movement restriction) or the stress hormone corticosterone (intraperitoneal injection of corticosterone), on spatial memory consolidation in adult male Wistar rats in two different post-training time windows (immediately or 3 hours after training) involved in memory consolidation. Rats were trained in a spatial memory task in the Barnes maze and a memory retention test was performed twenty-four hours after training. The results showed that both stress and corticosterone were able to enhance memory consolidation when they were administered immediately after training. However, when the same treatments were administered three hours after training, there was not a significant change in the performance during the test carried out after twenty-four hours. These results suggest, on the one hand, that memory consolidation process can be improved using treatments that modulate cellular gene expression programs, as stress and corticosterone, when they are applied during the first window of memory consolidation. Additionally, although the second period of memory consolidation is also related to a particular gene expression and protein synthesis program, the treatments used in the present study were not able to modulate memory consolidation when administered during this period. As the molecular events involved in the second window of memory consolidation may be different from those involved in the first one, it is possible that the molecular changes generated by stress and corticosterone do not interact with them in a way that affect memory formation. Figure 1 Acknowledgements Facultad de Ciencias Humanas, Universidad Nacional de Colombia. Call for research Orlando Fals Borda 2013 A (supporting researchers at Facultad de Ciencias Humanas). Project "Effects of systemic injection of corticosterone in two post-training periods, on the consolidation of a spatial memory task in the Barnes maze and the spatio-temporal pattern of expression of c-Fos and BDNF proteins". HERMES Project Number: 17719. References Alberini, C.& Taubenfeld, S. (2008). Memory Reconsolidation. Mount Sinai School of Medicine, New York, USA. Bekinschtein, P., Cammarota, M., Müller, L., Bevilaqua, L., Izquierdo, I. & Medina, J. (2007). Persistence of Long-Term Memory Storage Requires a Late Protein Synthesis- and BDNF-Dependent Phase in the Hippocampus. Neuron, 53, 261–277. Brivanlou, A. & Darnell, J. (2002). Signal transduction and the control of gene expression. Science, 295, 813-818. Chrousos, G., Loriaux, L. & Gold, P. (1988). The concept of stress and its historical development. En: Chrousos, G., Loriaux, L., & Gold, P., eds. Mechanisms of physical and emotional stress, 245. Advances in experimental medicine and biology (pp. 3-7). New York: Plenum Press. Igaz, L., Vianna, M., Medina, J. &Izquierdo, I., (2002). Two Time Periods of Hippocampal mRNA Synthesis Are Required for Memory Consolidation of Fear-Motivated Learning. The Journal of Neuroscience, 22(15), 6781–6789. Meeter, M. & Murre, J. (2004). Consolidation of long-term memory: evidence and alternatives. Psychological Bulletin, 130(6), 843-857. Mileusnic, R. (2004). Protein synthesis II: new proteins. In: Riedel, Gernot and Platt, Bettina Ed. From messengers to molecules: memories are made of these. Neuroscience Intelligence Unit Series. USA: Landes Bioscience, 529–542. Selye, H. (1976). Stress without Distress. Psychopathology of Human Adaptation, 137-146.Wittenber, G. & Tsien, J. (2002). An emerging molecular and cellular framework for memory processing by the hippocampus. Trends in Neurosciences, 25(10), 501-505. Tsigos, C. & Chrousos, G. (2002). Hypothalamic–pituitary–adrenal axis, neuroendocrine factors and stress. Journal of Psychosomatic Research, 53, 865–871. Wittenber, G. & Tsien, J. (2002). An emerging molecular and cellular framework for memory processing by the hippocampus. Trends in Neurosciences, 25(10), 501-505. Keywords: stress, Corticosterone, memory consolidation, spatial memory, Wistar rat. Conference: Latin-American School on glial cells in the diseased brain (IBRO), Bogotá, Colombia, 13 Jul - 17 Jul, 2015. Presentation Type: Poster Presentation Topic: Neural excitability, synaptic transmission, glia: Cellular and molecular mechanisms Citation: Cerón JM and Lamprea Rodríguez M (2015). Effects of stress and corticosterone in two post-training periods, on spatial memory consolidation in adult male Wistar rats.. Conference Abstract: Latin-American School on glial cells in the diseased brain (IBRO). doi: 10.3389/conf.fncel.2015.35.00013 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 11 Apr 2015; Published Online: 11 Jun 2015. * Correspondence: Miss. Jeimmy M Cerón, Universidad Nacional de Colombia, Departamento de Psicología, Bogotá, Colombia, jmcerong@gmail.com Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. 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