Memory Research Laboratory, Brain Institute, Federal University of Rio Grande do Norte, 59078-900 Natal, RN, Brazil; Departament of Physiology, Federal University of Rio Grande do Norte, 59064-741 Natal, RN, Brazil.
Memory Research Laboratory, Brain Institute, Federal University of Rio Grande do Norte, 59078-900 Natal, RN, Brazil; Edmond & Lily Safra International Institute of Neuroscience, 59280-000 Macaiba, RN, Brazil.
Brain Res Bull. 2023 Jun 1;197:42-48. doi: 10.1016/j.brainresbull.2023.03.013. Epub 2023 Apr 1.
Object recognition memory (ORM) allows identification of previously encountered items and is therefore crucial for remembering episodic information. In rodents, reactivation during recall in the presence of a novel object destabilizes ORM and initiates a Zif268 and protein synthesis-dependent reconsolidation process in the hippocampus that links the memory of this object to the reactivated recognition trace. Hippocampal NMDA receptors (NMDARs) modulate Zif268 expression and protein synthesis and regulate memory stability but their possible involvement in the ORM destabilization/reconsolidation cycle has yet to be analyzed in detail. We found that, in adult male Wistar rats, intra dorsal-CA1 administration of the non-subunit selective NMDAR antagonist AP5, or of the GluN2A subunit-containing NMDAR antagonist TCN201, 5 min after an ORM reactivation session in the presence of a novel object carried out 24 h post-training impaired retention 24 h later. In contrast, pre-reactivation administration of the GluN2B subunit-containing NMDAR antagonist RO25-6981 had no effect on ORM recall or retention but impeded the amnesia caused by Zif268 silencing and protein synthesis inhibition in dorsal CA1. Our results indicate that GluN2B-containing hippocampal NMDARs are necessary for ORM destabilization whereas GluN2A-containing NMDARs are involved in ORM reconsolidation, and suggest that modulation of the relative activity of these receptor subtypes during recall regulates ORM persistence.
物体识别记忆 (ORM) 允许识别先前遇到的项目,因此对于记忆情景信息至关重要。在啮齿动物中,在新物体存在的情况下回忆时的重新激活会破坏 ORM,并在海马体中引发 Zif268 和依赖蛋白质合成的再巩固过程,将该物体的记忆与重新激活的识别痕迹联系起来。海马体 NMDA 受体 (NMDAR) 调节 Zif268 的表达和蛋白质合成,并调节记忆稳定性,但它们在 ORM 破坏/再巩固循环中的可能参与尚未得到详细分析。我们发现,在成年雄性 Wistar 大鼠中,在 ORM 再激活后 5 分钟内,在新物体存在的情况下进行 24 小时后进行的训练,在背侧 CA1 内给予非亚基选择性 NMDAR 拮抗剂 AP5 或含有 GluN2A 亚基的 NMDAR 拮抗剂 TCN201,会损害 24 小时后的保留。相比之下,预先给予含有 GluN2B 亚基的 NMDAR 拮抗剂 RO25-6981 对 ORM 回忆或保留没有影响,但会阻碍背侧 CA1 中 Zif268 沉默和蛋白质合成抑制引起的健忘症。我们的结果表明,含有 GluN2B 的海马体 NMDAR 对于 ORM 破坏是必需的,而含有 GluN2A 的 NMDAR 参与 ORM 再巩固,并且表明在回忆过程中调节这些受体亚型的相对活性可以调节 ORM 的持续存在。