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    Participação da formação hipocampal dorsal na modulação do medo condicionado: análise comportamental e proteica
    (Universidade Federal de São Paulo, 2018-09-20) Gaiardo, Renan Barretta [UNIFESP]; Cerutti, Suzete Maria [UNIFESP]; Universidade Federal de São Paulo (UNIFESP)
    Behavioral and molecular data from our laboratory showed that the hippocampal formation participates in the formation of the memory of the conditioned suppression of the licking response. However, it does not clarify the molecular substrates involved in the different stages of the memory formation, evocation and extinction, and the process of long-term memory transfer from the hippocampus to other cortical structures. In this sense, the objective of this work was to study the protein alterations underlying the acquisition, evocation and extinction of conditioned fear memory in the dorsal and ventral hippocampal formation of rats submitted to the suppression of the licking response. For this study, male Wistar rats, randomly distributed in ten experimental groups and divided into two experiments, were used. After acquisition of the lick response (5 days), each rat was submitted to four associations between soundshock with five minutes interval (6th day). Suppression of licking behavior was measured by consecutive CS presentations in the test. The time taken to complete 10 licks in the presence and absence of CS in the test was used to calculate the suppression rate (SR) for each animal. For experiment 1, the protein profile of the dorsal hippocampal formation of the animals tested 2 or 40 days after conditioning and with euthanasia time of 24 hours after the test were compared. The data show that animals have acquired the memory of conditioned fear and that this event is gaining a new meaning over time, the sound fails to indicate something dangerous and retakes its original meaning. They also show for the first time that the test performed 40 days after the training does not interfere in the retention of the task, considering that the animals presented TS values equal to the other controls. Protein profile analysis resulted in 1,165 identified proteins and 265 quantified proteins, 38 of which had significant differential expression and seven proteins were unique. Protein interaction analysis indicated changes in myelin sheath pathways, neuronal generation and differentiation, regulation of neurogenesis and synaptic vesicle transport, axonal development, and the growth cone. For the experiment 2, we analyzed the expression of seven different signal transduction pathways in two euthanasia times (1 and 24 hours) in different stages of the experimental protocol: training, acquisition retention test (1 or 10 trials) and extinction retention test. The data indicated that the acquisition, consolidation and extinction of conditioned suppression comprises morphological changes in the dorsal and ventral hippocampal formation and alter the expression of BDNF, calcineurin A, CaMKII, calcium channel, CREB, PI3K and PKC, proteins that are involved in the long-term potentiation, the main cellular alteration for the consolidation of memories.