Análise dos marcadores moleculares associados a formação de memória de supressão condicionada na formação hipocampal dorsal e ventral
Data
2018-11
Autores
Kubota, Silvia Megumi 
Orientadores
Cerutti, Suzete Maria
Tipo
Trabalho de conclusão de curso
Título da Revista
ISSN da Revista
Título de Volume
Resumo
A formação hipocampal tem sido descrita como uma estrutura chave na consolidação de memórias de longa duração, do tipo declarativa, isto é, memórias que requerem a consciência do indivíduo durante sua evocação ou lembrança de informações sobre ambientes, pessoas ou objetos. Poucos estudos avaliam o papel da FH (formação hipocampal) na supressão de um comportamento em curso em detrimento do aumento da atenção e vigilância. Este estudo avaliou o papel da formação hipocampal dorsal e ventral na formação da memória de supressão condicionada por meio da análise da expressão diferencial da proteína cálcio -calmodulina – quinase II α (CaMKIIα), conhecidamente envolvida no processo de
formação e da extinção do medo condicionado. Para isso, foram utilizados ratos Wistar, machos, adultos, distribuídos aleatoriamente em nove grupos experimentais (n=10/grupo), sendo eles: controle, condicionamento, teste 1 com uma tentativa, teste 1 com 10 tentativas e teste 3 com 10 tentativas, todos com eutanásia após 1 hora e 24 horas. O protocolo comportamental envolveu: i) aquisição da resposta de lamber (1º ao 5º dia); ii) aquisição da memória de supressão condicionada da resposta de lamber, por meio da associação som (CS, estímulo condicionado) e choque (US, estímulo incondicionado) (6
O dia); iii) reaquisição da resposta de lamber (7º dia) e iv) teste para avaliar a retenção da memória de supressão condicionada (8º dia). No teste 1 (8º dia) os animais foram submetidos a 1 ou 10
exposições ao CS- sem associação com US. No teste 2 ou 3 (9º e 10º dia) foram apresentados 10 CS-sem US. 1 hora ou 24 horas após o teste os animais foram eutanasiados para a retirada da formação hipocampal dorsal e ventral e a expressão proteica diferencial, avaliada pela técnica de Western blotting. Os dados mostraram que houve uma redução nos níveis de pCaMKII/CaMKII, no hipocampo dorsal (P<0,05) e ventral (P<0,05) dos animais submetidos ao teste de retenção com 10 tentativas de exposição ao CS, em comparação com o grupo controle. Os níveis reduzidos de pCaMKII podem estar relacionados a extinção da memória de supressão condicionada. Dados adicionais podem esclarecer sobre os diferentes níveis proteicos de CaMKII e pCaMKIIα em cada um dos subcampos que compõem a formação hipocampal dorsal e ventral.
The hippocampal formation (HF) has been described as a key structure in the consolidation of longterm memories, of the declarative type, that is, memories that require the awareness of the individual during their evocation or the recollection of information about surroundings, people or objects. Few studies evaluate the role of the HF (hippocampal formation) in the suppression of ongoing behavior to the detriment of increased attention and vigilance. This study assessed the role of dorsal and ventral hippocampal formation in the formation of conditioned suppression memory by the differential expression analysis of the αcalcium/ calmodulindependent protein kinase II (αCaMKII), known to be involved in the process of fear conditioned memory formation and extinction. For this, male Wistar rats were randomly distributed in nine experimental groups (n = 10 / group), being: control, conditioning, test 1 with one attempt, test 1 with 10 trials and test 3 with 10 trials, all with euthanasia after 1 hour and 24 hours. The behavioral protocol involved: i) acquisition of the licking response (1st to 5th day); ii) acquisition of the conditioned suppression memory of the licking response, by means of the association sound (CS, conditioned stimulus) and shock (US, unconditioned stimulus) (6th day); iii) reacquisition of the licking response (7th day) and iv) test to evaluate conditioned suppression memory retention (8th day). In test 1 (8th day) the animals were submitted to 1 or 10 CSexposures without association with US. In test 2 or 3 (9th and 10th day) 10 CSwithout US were presented. 1 hour or 24 hours after the test the animals were euthanized for the removal of the dorsal and ventral hippocampal formation and the differential protein expression, evaluated by Western blotting technique. The data showed that there was a reduction in the levels of pCaMKII / CaMKII, in the dorsal (P <0.05) and ventral (P <0.05) hippocampus of the animals submitted to the retention test with 10 attempts of CS exposure, in comparison with the control group. Reduced levels of pCaMKII may relate to entinction of conditioned suppression memory. Additional data may clarify the different protein levels of CaMKII and pCaMKIIα in each of the subfields that make up the dorsal and ventral hippocampal formation.
The hippocampal formation (HF) has been described as a key structure in the consolidation of longterm memories, of the declarative type, that is, memories that require the awareness of the individual during their evocation or the recollection of information about surroundings, people or objects. Few studies evaluate the role of the HF (hippocampal formation) in the suppression of ongoing behavior to the detriment of increased attention and vigilance. This study assessed the role of dorsal and ventral hippocampal formation in the formation of conditioned suppression memory by the differential expression analysis of the αcalcium/ calmodulindependent protein kinase II (αCaMKII), known to be involved in the process of fear conditioned memory formation and extinction. For this, male Wistar rats were randomly distributed in nine experimental groups (n = 10 / group), being: control, conditioning, test 1 with one attempt, test 1 with 10 trials and test 3 with 10 trials, all with euthanasia after 1 hour and 24 hours. The behavioral protocol involved: i) acquisition of the licking response (1st to 5th day); ii) acquisition of the conditioned suppression memory of the licking response, by means of the association sound (CS, conditioned stimulus) and shock (US, unconditioned stimulus) (6th day); iii) reacquisition of the licking response (7th day) and iv) test to evaluate conditioned suppression memory retention (8th day). In test 1 (8th day) the animals were submitted to 1 or 10 CSexposures without association with US. In test 2 or 3 (9th and 10th day) 10 CSwithout US were presented. 1 hour or 24 hours after the test the animals were euthanized for the removal of the dorsal and ventral hippocampal formation and the differential protein expression, evaluated by Western blotting technique. The data showed that there was a reduction in the levels of pCaMKII / CaMKII, in the dorsal (P <0.05) and ventral (P <0.05) hippocampus of the animals submitted to the retention test with 10 attempts of CS exposure, in comparison with the control group. Reduced levels of pCaMKII may relate to entinction of conditioned suppression memory. Additional data may clarify the different protein levels of CaMKII and pCaMKIIα in each of the subfields that make up the dorsal and ventral hippocampal formation.