Methylprednisolone as a memory enhancer in rats: Effects on aversive memory, long-term potentiation and calcium influx

Liane da Silva de Vargas; Rithiele Gonçalves; Marcus Vinícius S Lara; Zaquer S M Costa-Ferro; Simone Denise Salamoni; Michelle Flores Domingues; Angela Regina Piovesan; Dênis Reis de Assis; Lucia Vinade; Alexandre P Corrado; Wilson Alves-Do-Prado; Paulo Correia-de-Sá; Jaderson Costa da Costa; Ivan Izquierdo; Cháriston A Dal Belo; Pâmela B Mello-Carpes

doi:10.1016/j.brainres.2017.06.007

Methylprednisolone as a memory enhancer in rats: Effects on aversive memory, long-term potentiation and calcium influx

Brain Res. 2017 Sep 1:1670:44-51. doi: 10.1016/j.brainres.2017.06.007. Epub 2017 Jun 9.

Authors

Liane da Silva de Vargas¹, Rithiele Gonçalves¹, Marcus Vinícius S Lara¹, Zaquer S M Costa-Ferro², Simone Denise Salamoni², Michelle Flores Domingues³, Angela Regina Piovesan³, Dênis Reis de Assis², Lucia Vinade⁴, Alexandre P Corrado⁵, Wilson Alves-Do-Prado⁶, Paulo Correia-de-Sá⁷, Jaderson Costa da Costa², Ivan Izquierdo⁸, Cháriston A Dal Belo⁴, Pâmela B Mello-Carpes⁹

Affiliations

¹ Physiology Research Group, Federal University of Pampa, Uruguaiana, RS, Brazil.
² Laboratory of Neuroscience, Brain Institute of Rio Grande do Sul, InsCer, PUCRS, Porto Alegre, RS, Brazil.
³ Graduate Program in Cell and Molecular Biology, Center of Biotechnology, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil; Laboratory of Neurotoxins, Laneurotox, Brain Institute of Rio Grande do Sul, InsCer, PUCRS, Porto Alegre, RS, Brazil.
⁴ Laboratory of Neurobiology and Toxinology, Lanetox, Federal University of Pampa, São Gabriel, RS, Brazil.
⁵ Department of Pharmacology, FMRP, University of São Paulo, Ribeirão Preto, SP, Brazil.
⁶ Department of Pharmacology and Therapeutics, State University of Maringa, PR, Brazil.
⁷ Laboratory of Pharmacology and Neurobiology, Center for Drug Discovery and Innovative Medicines (MedInUP), Instituto de Ciências Biomédicas de Abel Salazar, Universidade do Porto, Portugal.
⁸ Centre of Memory, Brain Institute of Rio Grande do Sul, InsCer, PUCRS, Porto Alegre, RS, Brazil.
⁹ Physiology Research Group, Federal University of Pampa, Uruguaiana, RS, Brazil. Electronic address: pamelacarpes@unipampa.edu.br.

PMID: 28606783
DOI: 10.1016/j.brainres.2017.06.007

Abstract

It is well recognized that stress or glucocorticoids hormones treatment can modulate memory performance in both directions, either impairing or enhancing it. Despite the high number of studies aiming at explaining the effects of glucocorticoids on memory, this has not yet been completely elucidated. Here, we demonstrate that a low daily dose of methylprednisolone (MP, 5mg/kg, i.p.) administered for 10-days favors aversive memory persistence in adult rats, without any effect on the exploring behavior, locomotor activity, anxiety levels and pain perception. Enhanced performance on the inhibitory avoidance task was correlated with long-term potentiation (LTP), a phenomenon that was strengthen in hippocampal slices of rats injected with MP (5mg/kg) during 10days. Additionally, in vitro incubation with MP (30-300µM) concentration-dependently increased intracellular [Ca²⁺]_i in cultured hippocampal neurons depolarized by KCl (35mM). In conclusion, a low daily dose of MP for 10days may promote aversive memory persistence in rats.

Keywords: Aversive memory; Glucocorticoids; Inhibitory avoidance; Long-term potentiation.

MeSH terms

Animals
CA1 Region, Hippocampal / drug effects
Calcium / metabolism
Hippocampus / drug effects
Long-Term Potentiation / drug effects*
Male
Memory / classification
Memory / drug effects*
Memory / physiology
Methylprednisolone / metabolism
Methylprednisolone / pharmacology*
Rats
Rats, Wistar
Synapses / physiology

Substances

Calcium
Methylprednisolone