Pharmacological blockage and P2X7 deletion hinder aversive memories: Reversion in an enriched environment

R.C. Campos, G.M. Parfitt, C.E. Polese, R. Coutinho-Silva, F.B. Morrone, D.M. Barros
Neuroscience. 2014-11-01; 280: 220-230
DOI: 10.1016/j.neuroscience.2014.09.017

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Campos RC(1), Parfitt GM(1), Polese CE(2), Coutinho-Silva R(3), Morrone FB(4),
Barros DM(5).

Author information:
(1)Programa de Pós-graduação em Ciências Fisiológicas – Fisiologia Animal
Comparada, Instituto de Ciências Biológicas, Laboratório de Neurociências,
Universidade Federal do Rio Grande (FURG), Rio Grande, RS 96203-900, Brazil.
(2)Instituto de Ciências Biológicas, Laboratório de Neurociências, Universidade
Federal do Rio Grande (FURG), Rio Grande, RS 96203-900, Brazil.
(3)Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de
Janeiro (UFRJ), Brazil.
(4)Instituto de Toxicologia e Farmacologia, Pontifícia Universidade Católica de
Porto Alegre (PUC-RS), Brazil.
(5)Programa de Pós-graduação em Ciências Fisiológicas – Fisiologia Animal
Comparada, Instituto de Ciências Biológicas, Laboratório de Neurociências,
Universidade Federal do Rio Grande (FURG), Rio Grande, RS 96203-900, Brazil;
Instituto de Ciências Biológicas, Laboratório de Neurociências, Universidade
Federal do Rio Grande (FURG), Rio Grande, RS 96203-900, Brazil. Electronic
address: .

Adenosine triphosphate (ATP) plays a role in cell signaling. It was soon
proposed that ATP activates ionotropic P2X receptors, exerting an influence on
neurons as well as on glial cells. In addition to the fact that the activation
of P2X and P2Y receptors can stimulate or inhibit the release of glutamate from
rat hippocampal neurons, the release of ATP has been implicated in hippocampal
long-term potentiation (LTP). Through different behavioral paradigms, this study
aimed to investigate the participation of P2X7R in genetically modified
(knockout (KO)) mice with the suppressed expression of this receptor and in the
pharmacological blockage of this receptor in rats, as well as to evaluate the
effect of environmental enrichment on potential mnemonic deficits. The results
suggest that P2X7R participates in aversive memory processes: pharmacological
blockage with the selective P2X7R antagonist, A-740003, in different time frames
elicited dose-dependent impairments in memory acquisition, consolidation and
retrieval in rats that were submitted to the contextual fear-conditioning (FC)
task, and the deletion of P2X7R hampered the aversive memory processes of mice
that were subjected to the FC paradigm. Experiments using mice that were
subjected to environmental enrichment suggest that this form of stimulation
reverses mnemonic impairments that are ascribed to the absence of the P2X7R,
suggesting that these receptors do not participate on such a reversal. Finally,
no alterations were observed in the habituation memory of P2X7KO mice.