The expression of contextual fear conditioning involves activation of a NMDA receptor-nitric oxide-cGMP pathway in the dorsal hippocampus of rats

Autor(es)

Fabri, Denise R. S. ^[1] ; Hott, Sara C. ^{[1, 2]} ; Reis, Daniel G. ^{[1, 2]} ; Biojone, Caroline ^{[1, 2]} ; Correa, Fernando M. A. ^[1] ; Resstel, Leonardo B. M. ^{[1, 2]}

Afiliação do(s) autor(es)

^[1] Univ Sao Paulo, Sch Med Ribeirao Preto, Dept Pharmacol, BR-14049900 Ribeirao Preto, SP - Brazil

^[2] Univ Sao Paulo, Ctr Interdisciplinary Res Appl Neurosci, BR-14049900 Ribeirao Preto, SP - Brazil

• Tipo de documento: Artigo Científico
• Fonte: European Neuropsychopharmacology; v. 24, n. 10, p. 1676-1686, OCT 2014.
• Citações Web of Science: 12

Resumo

The dorsal portion of the hippocampus is a limbic structure that is involved in fear conditioning modulation in rats. Moreover, evidence shows that the local dorsal hippocampus glutamatergic system, nitric oxide (NO) and cGMP modulate behavioral responses during aversive situations. Therefore, the present study investigated the involvement of dorsal hippocampus NMDA receptors and the NO/cGMP pathway in contextual fear conditioning expression. Male Wistar rats were submitted to an aversive contextual conditioning session and 48 h later they were re-exposed to the aversive context in which freezing, cardiovascular responses (increase of both arterial pressure and heart rate) and decrease of tail temperature were recorded. The intra-dorsal hippocampus administration of the NMDA receptor antagonist AP7, prior to the re-exposure to the aversive context, attenuated fear-conditioned responses. The re-exposure to the context evoked an increase in NO concentration in the dorsal hippocampus of conditioned animals. Similar to AP7 administration, we observed a reduction of contextual fear conditioning after dorsal hippocampus administration of either the neuronal NO synthase inhibitor N-propyl-L-arginine, the NO scavenger c-PTIO or the guanylate cyclase inhibitor ODQ. Therefore, the present findings suggest the possible existence of a dorsal hippocampus NMDA/NO/cGMP pathway modulating the expression of contextual fear conditioning in rats. (C) 2014 Elsevier B.V. and ECNP. All rights reserved. (AU)

• Processo FAPESP: 11/07332-3 - Estudo do envolvimento do hipocampo dorsal de ratos nas respostas comportamentais e autonômicas associadas a reações de defesa: uma possível via receptores NMDA/óxido nítrico e endocanabinóides
• Beneficiário: Leonardo Resstel Barbosa Moraes
• Linha de fomento: Auxílio à Pesquisa - Regular
• Processo FAPESP: 12/09300-4 - O sistema noradrenérgico presente no núcleo leito da estria terminal modula a resposta emocional condicionada contextual: uma possível interação com o CRF e as neurotransmissões glutamatérgica e nitrérgica
• Beneficiário: Leonardo Resstel Barbosa Moraes
• Linha de fomento: Auxílio à Pesquisa - Regular