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(Referência obtida automaticamente do Web of Science, por meio da informação sobre o financiamento pela FAPESP e o número do processo correspondente, incluída na publicação pelos autores.)

Further evidence for involvement of the dorsal hippocampus serotonergic and gamma-aminobutyric acid (GABA) ergic pathways in the expression of contextual fear conditioning in rats

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Autor(es):
Almada, Rafael C. [1, 2] ; Albrechet-Souza, Lucas [1, 2] ; Brandao, Marcus L. [1, 2]
Número total de Autores: 3
Afiliação do(s) autor(es):
[1] Univ Sao Paulo, Fac Filosofia Ciencias & Letras Ribeirao Preto, Lab Neuropsicofarmacol, BR-14040901 Ribeirao Preto, SP - Brazil
[2] Inst Neurociencias & Comportamento INeC, Ribeirao Preto - Brazil
Número total de Afiliações: 2
Tipo de documento: Artigo Científico
Fonte: JOURNAL OF PSYCHOPHARMACOLOGY; v. 27, n. 12, SI, p. 1160-1168, DEC 2013.
Citações Web of Science: 5
Resumo

Intra-dorsal hippocampus (DH) injections of 8-hydroxy-2-(di-n-propylamino) tetralin (8-OH-DPAT), a serotonin-1A (5-hydroxytryptamine (5-HT)-1A) receptor agonist, were previously shown to inhibit the expression of contextual fear when administered six hours after conditioning. However, further understanding of the consolidation and expression of aversive memories requires investigations of these and other mechanisms at distinct time points and the regions of the brain to which they are transferred. Thus, the purpose of the present study was to investigate the role of DH serotonergic and -aminobutyric acid (GABA)ergic mechanisms in the expression of contextual fear 24 h after conditioning, reflected by fear-potentiated startle (FPS) and freezing behavior. The recruitment of the amygdala and medial prefrontal cortex (mPFC) in these processes was also evaluated by measuring Fos protein immunoreactivity. Although intra-DH injections of 8-OH-DPAT did not produce behavioral changes, muscimol reduced both FPS and the freezing response. Fos protein immunoreactivity revealed that contextual fear promoted wide activation of the mPFC, which was significantly reduced after intra-DH infusions of muscimol. The present findings, together with previous data, indicate that in contrast to 5-HT, which appears to play a role during the early phases of contextual aversive memory consolidation, longer-lasting GABA-mediated mechanisms are recruited during the expression of contextual fear memories. (AU)

Processo FAPESP: 11/00041-3 - Neurobiologia do estresse: a interface sensório-motora
Beneficiário:Marcus Lira Brandão
Linha de fomento: Auxílio à Pesquisa - Temático