Spermidine (SPD) is an endogenous polyamine that plays a facilitatory role in memory acquisition and consolidation. Memory consolidation occurs immediately after learning and again around 3−6 hours later. Current evidence indicates that the polyamine binding site at the NMDA receptor (NMDAr) mediates the effects of SPD on memory. While NMDAr activation increases brain-derived neurotrophic factor (BDNF) release, no study has investigated whether BDNF-activated signaling pathways, such as the phosphatidylinositol 3-kinase (PI3K)/Akt pathway play a role in SPD-induced improvement of memory consolidation. Therefore, the aim of the current study was to evaluate whether the TrkB receptor and the PI3K/Akt pathway are involved in the facilitatory effect of SPD on memory consolidation. Male Wistar rats were trained in the contextual conditioned fear task. SPD, ANA-12 (TrkB antagonist), and LY294002 (PI3K inhibitor) were administered immediately after training. The animals were tested 24 h after training. We found that SPD improved fear memory consolidation and that both ANA-12 and LY294002 prevented the facilitatory effect of SPD on memory. These results suggest that SPD-induced improvement of memory consolidation involves the activation of the TrkB receptor and PI3K/Akt pathway.

亚精胺 (SPD) 是一种内源性多胺，在记忆获得和巩固中起促进作用。学习后立即发生记忆巩固，大约 3-6 小时后再次巩固。目前的证据表明，NMDA 受体 (NMDAr) 上的多胺结合位点介导了 SPD 对记忆的影响。虽然 NMDAr 激活增加了脑源性神经营养因子 (BDNF) 的释放，但没有研究调查 BDNF 激活的信号通路，如磷脂酰肌醇 3-激酶 (PI3K)/Akt 通路是否在 SPD 诱导的记忆巩固改善中发挥作用。因此，本研究的目的是评估 TrkB 受体和 PI3K/Akt 通路是否参与了 ​​SPD 对记忆巩固的促进作用。雄性 Wistar 大鼠接受了情境条件恐惧任务的训练。训练后立即给予 SPD、ANA-12（TrkB 拮抗剂）和 LY294002（PI3K 抑制剂）。训练后24小时对动物进行测试。我们发现 SPD 改善了恐惧记忆巩固，ANA-12 和 LY294002 都阻止了 SPD 对记忆的促进作用。这些结果表明，SPD 诱导的记忆巩固改善涉及 TrkB 受体和 PI3K/Akt 通路的激活。