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EPA-1260 – Gene-environment Interplay in the Influence of Early Life Stress on Emotionality
- E. De Lana Meirelles, R. Lopes, J. Landeira-Fernandez, P.F. Gardino
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- Journal:
- European Psychiatry / Volume 29 / Issue S1 / 2014
- Published online by Cambridge University Press:
- 15 April 2020, p. 1
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The emotional behavior is influenced by several factors, including environment, genetic and the interaction between them, which is the aim of this work. Early life stress has been related to the development of emotional disturbances late in life, nevertheless recent studies have showed a new operational model to this relation, depending on the genetic background. Regarding to depression-like behavior, the most recent manuals for diagnosis of this disease highlights the importance of assess the anhedonia, more than the blue mood, to a correct identification of this pathology. Animal models of affective disorders has been developed aiming to access all range of depressive-like behaviors. A behavioral test to evaluate this lowest tendency to attend pleasure situations is the Sucrose Preference Test (SPT). The neonatal maternal separation procedure was carried out with the Carioca rats, an anxiety disorder Wistar rat model, developed through selective lines matching based in a task of contextual fear conditioning, which gives rise to two different lines: CHF (Carioca High Freezing) and CLF (Carioca Low Freezing). Six CHF and 10 CLF animals were used in this work. We also used Maternal Separated AFR (Animal Facility Rearing) (n=15) and Non-separated AFR groups as controls (CTR group, n=8). The rat pups were separated as a litter (8 to 10 animals per dam) from the dam from post natal day (PND) 1–14, daily, for a three-hour period/day (MS-CHF, MS-CLF and MS-AFR groups); the CTR group did not receive any kind of manipulation in these 14 days, exception for the home cage cleaning once a week, performed for all groups. The weaning was performed at PND21. All the animals were tested in the SPT at PND 60, using a 10% sucrose-solution. The animals were grouped in 4–6 animals and were tested in a free choice protocol for 48 hours. In the first 12 hours, the animals were trained with two bottles of water in the cage. After this, there were two bottles for each cage: one with water and the other with the 10% sucrose solution. The bottles' location was changed often to avoid possible position preference. The total liquid consumption and then thee sucrose consumption ratio were measured. The Kruskal-Wallis test was used to evaluate the differences between the three MS groups. The Dunn's post hoc test showed a difference between the groups in relation to relative sucrose consumption: MS-CHF consumed less sucrose solution than the MS-CLF and MS-AFR groups (KW: 24.02; p<0.001). A Student t test between MS-AFR and CRT groups showed that MS-AFR animals consumed less sucrose solution than CTR group (t=3.372, df=21; p=0.0029), which serves as a control for the Maternal Separation protocol used in this work. These data suggest that maternal separation protocol was able to reduce the sucrose preference in these animals. However, this influence appears to be mediated by the genetic background, reinforce the new operation model to understand the emotional disorders etiology. The authors thank CAPES, FAPERJ and CNPq for the financial support.
EPA-1266 – Anxiety Behavior Extinction is Influenced By Early Environment in a Genetic Background-Dependent Way
- E. De Lana Meirelles, F.P. Rosseti, C.E. Barroso, J. Landeira-Fernandez, F.P. Gardino
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- Journal:
- European Psychiatry / Volume 29 / Issue S1 / 2014
- Published online by Cambridge University Press:
- 15 April 2020, p. 1
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- Article
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- You have access Access
- Export citation
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Introduction:
Several factors influence the emotional behavior, including environment, genetic and the interaction between them.
Objective:The aim of this work is to investigate the interaction between environmental and genetic influences in the divergent behavior of Carioca High and Low Freezing (CHF and CLF) rats - a genetic model to study fear and anxiety. The Carioca rat lines were produced from selective breeding method, from animals with the highest and lowest levels of freezing behavior in the contextual fear conditioning, a model to study anxiety-like behavior.
Methods:To investigate the gene-environment interplay, we employed the cross-fostering procedure, which CHF rat pups were raised by CLF dams, and vice-versa, since pos natal day (PND) 1 until weaning at PND21. The litters were culled in 8 pups, and we fostered only 2–3 male pups per litter. We also maintained CHF and CLF control, no-fostered litters. On PND60, male animals of the four groups (CHF (n=7), CHF-CLF (CHF pups raised by CLF dams) (n=6), CLF (n=4) and CLF-CHF (n=3)) were exposed to the contextual fear conditioning.
Results:The freezing behavior on the day after foot shocks was analyzed. A two-way ANOVA showed that, although CHF rats had a higher time in freezing in this task comparing to the CLF (p<0.01), as expected, no one cross-fostering effect was observed: CHF = CHF-CLF > CLF-CHF = CLF. On PND120, the same male rats were exposed to a 12-minutes-session, two-session extinction paradigm, in the same context. In these sessions, no foot shock was used. Comparing the freezing time in the context session on the conditioning paradigm to the freezing time on the first extinction session, we observed a significant decrease in this behavior for the CHF-CLF group, but not in the CHF group (p<0.05). This difference between groups was not observed between CLF and CLF-CHF animals. Our previous work has showed that there isn’t a memory deficit in the CHF animals.
Conclusions:This data suggest an existence of an early environment influence in the anxiety behavior extinction, but it was dependent of the genetic background.