Banca de QUALIFICAÇÃO: ISABELLA MARIA DE OLIVEIRA PONTES FERNANDES
Uma banca de QUALIFICAÇÃO de DOUTORADO foi cadastrada pelo programa.DISCENTE : ISABELLA MARIA DE OLIVEIRA PONTES FERNANDES
DATA : 14/06/2017
HORA: 09:00
LOCAL: Sala de Reuniões do Centro de Biociências
TÍTULO:
PALAVRAS-CHAVES:
BDNF, 5-HT1A, aversive memory, anxiety, unpredictable chronic mild stress, mood-congruent memory, neurogenesis, neuronal death, Major depressive disorder, Chronic mild stress.
PÁGINAS: 68
GRANDE ÁREA: Ciências Humanas
ÁREA: Psicologia
RESUMO:
Depression is a serious mood disorder that affects a significant part of the population, mainly women. There are strong evidences suggesting stress as a predisposing factor to depression and women seems to be less resilient to stress becoming more susceptible to depression. Furthermore, the response to antidepressants seems to be different between sexes. Thus, it is necessary to study sexual differences in physiopathology and treatment response of depression. Various evidences link the implication of serotonergic system on depression’s physiopathology, besides the reduction of BDNF expression, increase of oxidative stress and pro-inflammatory cytokines, reduction of anti-inflammatory cytokines leading to a neurodegenerative pattern and, consequently, neuronal death. On the other hand, antidepressants may promote an improvement in depressive symptoms associated to increased neutrofins and neurogenesis. This work aims to investigate sexual differences on depressive-like behavior induced by chronic mild stress (CMS) and the response to chronic antidepressant treatment, through the evaluation of hedonic behavior, learned helplessness and neurotrofins, neurons, glial cells, serotonin and glucocorticoid receptors. Also is purpose of this work to assess CMS effect and antidepressant treatment on aversive memory and anxiety using discriminative avoidance in the elevated plus maze (DA) since depressed patients show cognitive deficts and antidepressant treatment demonstrated to potentiate aversive memory extinction besides de fact that there is a strong comorbidity of depression and anxiety disorders. For these purpose, animals will be submitted to CMS protocol and fluoxetin, nortriptilin or vehicle treatment. Anhedonia (main sympton of depression) will be evaluated through sucrose preference test (SPT) and sucrose splash test (SST). Forced swim test (FST) will be used to evaluate antidepressant effect. Aversive memory and anxiety will be assessed through DA, simultaneously. After this, animals will be euthanized and will be extracted blood, for corticosterone quantification, and brains for neurogenesis evaluation (through BrdU marking), neuronal death (GFAP), BDNF and 5-HT1A, CRH-1 and CRH-2 receptors. Pilot experiments were carried out in order to verify the CMS reproducibility in our lab conditions and to stabilish the sequence and duration of stressor stimuli, the beginning of the development of depressive symptoms and when to start the pharmacological treatment of the animals. According to our preliminary results, the animals showed increased immobility time in the FST in the period from 21 to 42 days when submitted to CMS. Although we did not observe differences in SPT and SST comparing sex and/or condition, when we compared only females in the SST separated by the phases of the estrous cycle we observed an increased time of grooming on females in the phases with elevated hormonal levels (proestrous and estrous). Based on these preliminary results, we conclude that the CMS model was able to induce learned helplessness but not anhedonia in both sexes. However, it was able to reduce self-care and hedonic behaviors only in stressed females in a hormone-dependent manner.
MEMBROS DA BANCA:
Interno - 1645202 - ELAINE CRISTINA GAVIOLI
Presidente - 2140860 - ROVENA CLARA GALVAO JANUARIO ENGELBERTH
Externo ao Programa - 1720860 - VANESSA DE PAULA SOARES RACHETTI