Dendritic spine density and EphrinB2 levels of hippocampal and anterior cingulate cortex neurons increase sequentially during formation of recent and remote fear memory in the mouse.
Behav Brain Res
; 344: 120-131, 2018 05 15.
Article
em En
| MEDLINE
| ID: mdl-29444449
ABSTRACT
Memory consolidation is a dynamic process that involves a sequential remodeling of hippocampal-cortical circuits. Although synaptic events underlying memory consolidation are well assessed, fine molecular events controlling this process deserve further characterization. To this aim, we challenged male C57BL/6N mice in a contextual fear conditioning (CFC) paradigm and tested their memory 24â¯h, 7 days or 36 days later. Mice displayed a strong fear response at all time points with an increase in dendritic spine density and protein levels of the cell adhesion factor EphrinB2 in CA1â¯hippocampal neurons 24â¯h and 7 days post conditioning (p.c.), and in anterior cingulate cortex (ACC) neurons 36 days p.c. We then investigated whether the formation of remote memory and neuronal modifications in the ACC would depend on p.c. protein synthesis in hippocampal neurons. Bilateral intrahippocampal infusions with the protein synthesis inhibitor anisomycin administered immediately p.c. decreased fear response, neuronal spine growth and EphrinB2 protein levels of hippocampal and ACC neurons 24â¯h and 36 days p.c., respectively. Anisomycin infusion 24â¯h p.c. had no effects on fear response, increase in spine density and in EphrinB2 protein levels in ACC neurons 36 days p.c. Our results thus confirm that early but not late p.c. hippocampal protein synthesis is necessary for the formation of remote memory and provide the first evidence of a possible involvement of EphrinB2 in neuronal plasticity in the ACC.
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Base de dados:
MEDLINE
Assunto principal:
Efrina-B2
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Espinhas Dendríticas
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Medo
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Região CA1 Hipocampal
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Giro do Cíngulo
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Memória
Idioma:
En
Ano de publicação:
2018
Tipo de documento:
Article