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| Author(s): |
Vítor Pansarim
Total Authors: 1
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| Document type: | Master's Dissertation |
| Press: | Ribeirão Preto. |
| Institution: | Universidade de São Paulo (USP). Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto (PCARP/BC) |
| Defense date: | 2021-04-27 |
| Examining board members: |
Andreia Schmidt;
Fábio Leyser Gonçalves;
Fernanda Klein Marcondes
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| Advisor: | Andreia Schmidt |
| Abstract | |
Exposure to chronic restraint stress (CRS) can induce changes in physiological and behavioral processes. Studies using this model have found contradictory results about its effects on spatial learning and the occurrence of behaviors related to anxiety and depression in rodents. These differences may be related to methodological variables, such as the time of exposure to CRS. In addition, few studies employ females, and there are indications that females may be more resistant to the effects of CRS than males. The present study aimed to investigate the interaction between the sex (males and females) of Sprague-Dawley rats and the duration of exposure to CRS (11 and 22 days) on: a) performance in a spatial learning task in the Morris water maze (MWM); b) the occurrence of behaviors associated with anhedonia in the test of preference for sucrose solution (SPT); c) the occurrence of behaviors associated with anxiety and exploration in the elevated plus maze (EPM); d) the percentage of weight gain and the estrous cycle composition. Eighty rats were allocated to eight experimental groups (10 subjects per group) according to sex (male or female), the intervention type (control or CRS) and the intervention duration (11 or 22 days). During the intervention, the experimental groups were exposed daily to the CRS for 6 hours. Throughout the procedure, the weight gain of the animals and the estrous cycle of the females were monitored, besides the SPTs that were conducted. The tests at EPM and MWM started the next day after the end of the intervention. It was observed that the 11-day CRS could induce a drop in the weight gain of males and females and to change the composition of the estrous cycle of some females, while the last 11 days of CRS did not cause changes in weight gain. Exposure to 11 days of CRS caused more anxiety-related behaviors in comparison with exposure to 22 days of CRS in males, but not in females. No effects of the CRS was verified on the performance of the groups in the MWM and in the SPTs. Thus, short-term chronic stress is capable of causing impairment, such as increased anxiety and a drop in weight gain, while prolonged chronic stress is capable of leading the organism to adapt, canceling initial losses. In addition, it is confirmed, as in other studies, that females may be more resistant to CRS than males. It is not clear which variables favor adaptation or prolongation of losses after 21 days of exposure to CRS, and further studies are needed to investigate the factors involved. (AU) | |
| FAPESP's process: | 19/03384-0 - Efect of chronic restraint stress on rats performance in a spatial learning task |
| Grantee: | Vítor Pansarim |
| Support Opportunities: | Scholarships in Brazil - Master |