title: Modulation of the consolidation and reconsolidation of fear memory by three different serotonin receptors in hippocampus.
abstract: The process of memory formation is complex and highly dynamic. During learning, the newly acquired information is found in a fragile and labile state. Through a process known as consolidation, which requires specific mechanisms such as protein synthesis, the memory trace is stored and stabilized. It is known that when a consolidated memory is recalled, it again becomes labile and sensitive to disruption. To be maintained, this memory must undergo an additional process of restabilization called reconsolidation, which requires another phase of protein synthesis. Memory consolidation has been studied for more than a century, while the molecular mechanisms underlying the memory reconsolidation are starting to be elucidated. For this, is essential compare the participation of important neurotransmitters and its receptors in both processes in brain regions that play a central role in the fear response learning. With focus on serotonin (5-HT), a well characterized neurotransmitter that has been strongly implicated in learning and memory, we investigated, in the CA1 region of the dorsal hippocampus, whether the latest discovered serotonergic receptors, 5-HT5A, 5-HT6and 5-HT7, are involved in the consolidation and reconsolidation of contextual fear conditioning (CFC) memory. For this, male rats with cannulae implanted in the CA1 region received immediately after the training or reactivation session, or 3h post-reactivation of the CFC, infusions of agonists or antagonists of the 5-HT5A, 5-HT6and 5-HT7receptors. After 24h, animals were subjected to a 3-min retention test. The results indicated that in the CA1 region of the hippocampus the 5-HT5A, 5-HT6and 5-HT7serotonin receptors participate in the reconsolidation of the CFC memory 3h post-reactivation. Additionally, the results suggest that the 5-HT6and 5-HT7receptors also participate in the consolidation of the CFC memory.
authors.affiliation: Memory Center, Brain Institute, Pontifical Catholic University of Rio Grande do Sul (PUCRS), Av. Ipiranga, 6690 - 2ndfloor, 90610-000 Porto Alegre, RS, Brazil.
authors.forename: S D
authors.initials: SD
authors.lastname: Schmidt
authors.affiliation: Memory Center, Brain Institute, Pontifical Catholic University of Rio Grande do Sul (PUCRS), Av. Ipiranga, 6690 - 2ndfloor, 90610-000 Porto Alegre, RS, Brazil; National Institute of Translational Neuroscience (INNT), National Research Council of Brazil, Brazil.
authors.forename: C R G
authors.initials: CRG
authors.lastname: Furini
authors.affiliation: Memory Center, Brain Institute, Pontifical Catholic University of Rio Grande do Sul (PUCRS), Av. Ipiranga, 6690 - 2ndfloor, 90610-000 Porto Alegre, RS, Brazil.
authors.forename: C G
authors.initials: CG
authors.lastname: Zinn
authors.affiliation: Memory Center, Brain Institute, Pontifical Catholic University of Rio Grande do Sul (PUCRS), Av. Ipiranga, 6690 - 2ndfloor, 90610-000 Porto Alegre, RS, Brazil.
authors.forename: L E
authors.initials: LE
authors.lastname: Cavalcante
authors.affiliation: Memory Center, Brain Institute, Pontifical Catholic University of Rio Grande do Sul (PUCRS), Av. Ipiranga, 6690 - 2ndfloor, 90610-000 Porto Alegre, RS, Brazil.
authors.forename: F F
authors.initials: FF
authors.lastname: Ferreira
authors.affiliation: Memory Center, Brain Institute, Pontifical Catholic University of Rio Grande do Sul (PUCRS), Av. Ipiranga, 6690 - 2ndfloor, 90610-000 Porto Alegre, RS, Brazil.
authors.forename: J A K
authors.initials: JAK
authors.lastname: Behling
authors.affiliation: Memory Center, Brain Institute, Pontifical Catholic University of Rio Grande do Sul (PUCRS), Av. Ipiranga, 6690 - 2ndfloor, 90610-000 Porto Alegre, RS, Brazil; National Institute of Translational Neuroscience (INNT), National Research Council of Brazil, Brazil. Electronic address: jociane_carvalho@hotmail.com.
authors.forename: J C
authors.initials: JC
authors.lastname: Myskiw
authors.affiliation: Memory Center, Brain Institute, Pontifical Catholic University of Rio Grande do Sul (PUCRS), Av. Ipiranga, 6690 - 2ndfloor, 90610-000 Porto Alegre, RS, Brazil; National Institute of Translational Neuroscience (INNT), National Research Council of Brazil, Brazil. Electronic address: izquier@terra.com.
authors.forename: I
authors.initials: I
authors.lastname: Izquierdo
mesh_terms: D000818:Animals; D003214:Conditioning, Classical / Q000187:drug effects; D005239:Fear / Q000187:drug effects*; D006624:Hippocampus / Q000187:drug effects*; D008297:Male; D008568:Memory / Q000187:drug effects*; D000069077:Memory Consolidation / Q000187:drug effects*; D051381:Rats; D017208:Rats, Wistar; D012702:Serotonin Antagonists / Q000494:pharmacology*; D017366:Serotonin Receptor Agonists / Q000494:pharmacology*
chemical_list: D012702:Serotonin Antagonists; D017366:Serotonin Receptor Agonists
keywords: Consolidation; Contextual fear conditioning; Reconsolidation; Serotoninergic receptors