IFEC   20925
INSTITUTO DE FARMACOLOGIA EXPERIMENTAL DE CORDOBA
Unidad Ejecutora - UE
artículos
Título:
Opposite action of hippocampal CB1 receptors in memory reconsolidation and extinction.
Autor/es:
LUCAS DE OLIVEIRA ALVARES; BRUNA P GENRO; FELIPE DIEHL, M.; VICTOR A MOLINA; JORGE A QUILLFELDT
Revista:
NEUROSCIENCE
Editorial:
Elsevier Science
Referencias:
Año: 2008 vol. 154 p. 1648 - 1655
ISSN:
0306-4522
Resumen:
Retrieval of a consolidated memory triggers a number
of processes which depend, among other factors, on the
duration of the reactivation session: reconsolidation requires a
brief reactivation session, and extinction, a prolonged one. The
scope of this study is to explore the potential role of the hippocampal
endocannabinoid system on reconsolidation and extinction
processes. Bilateral infusion of the CB1 cannabinoid
receptor antagonist, N-(piperidin-1-yl)-5-(4-iodophenyl)-1-(2, 4-dichlorophenyl)-
4-methyl-1H-pyrazole-3-carboxamide (AM251) into
the CA1 region of the dorsal hippocampus of Wistar rats after
memory reactivation facilitated the reconsolidation of the contextual
fear conditioning memory. The inhibition of protein synthesis
with DRB in the same brain region blocked memory
reconsolidation. Both effects were persistent, lasting up to 7
days after the first retrieval experience. In contrast, the local
infusion of anandamide blocked memory reconsolidation, an
effect that was antagonized by the combined administration of
anandamide with a subthreshold dose of a CB1 antagonist,
supporting a CB1-mediated role of the hippocampal endocannabinoid
system in the modulation of the memory reconsolidation.
Local infusion of AM251 into CA1 blocked memory extinction
whereas the administration of anandamide facilitated it;
however, when combined with a subthreshold concentration of
the CB1 antagonist, anandamide did not affect the extinction
process. The clear-cut, opposite effects observed in each situation
suggest a possible role of the hippocampal endocannabinoid
system as a switching mechanism deciding which processes
will take place, either maintaining the original memory
(reconsolidation) or promoting a new learning (extinction).
© 2008 IBRO. Published by Elsevier Ltd. All rights reserved.