de Vargas Liane da Silva, Gonçalves Rithiele, Lara Marcus Vinícius S, Costa-Ferro Zaquer S M, Salamoni Simone Denise, Domingues Michelle Flores, Piovesan Angela Regina, de Assis Dênis Reis, Vinade Lucia, Corrado Alexandre P, Alves-Do-Prado Wilson, Correia-de-Sá Paulo, da Costa Jaderson Costa, Izquierdo Ivan, Dal Belo Cháriston A, Mello-Carpes Pâmela B
Physiology Research Group, Federal University of Pampa, Uruguaiana, RS, Brazil.
Laboratory of Neuroscience, Brain Institute of Rio Grande do Sul, InsCer, PUCRS, Porto Alegre, RS, Brazil.
Brain Res. 2017 Sep 1;1670:44-51. doi: 10.1016/j.brainres.2017.06.007. Epub 2017 Jun 9.
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 [Ca] 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.
众所周知，压力或糖皮质激素治疗可在两个方向上调节记忆表现，既可能损害记忆，也可能增强记忆。尽管有大量研究旨在解释糖皮质激素对记忆的影响，但这一点尚未完全阐明。在此，我们证明，连续10天每天腹腔注射低剂量甲泼尼龙（MP，5mg/kg）有利于成年大鼠厌恶记忆的持续存在，对探索行为、运动活动、焦虑水平和疼痛感知没有任何影响。抑制性回避任务表现的增强与长时程增强（LTP）相关，LTP是一种在连续10天注射MP（5mg/kg）的大鼠海马切片中得到增强的现象。此外，在体外培养中，用MP（30 - 300µM）孵育能浓度依赖性地增加由氯化钾（35mM）去极化的培养海马神经元内的[Ca]。总之，连续10天每天给予低剂量MP可能促进大鼠厌恶记忆的持续存在。
