Takabayashi Kento, Kajita Yuki, Mushiake Hajime
Department of Physiology, Tohoku University School of Medicine, 2-1 Seiryo-machi, Aoba-ku, Sendai 980-8575, Japan.
Department of Physiology, Tohoku University School of Medicine, 2-1 Seiryo-machi, Aoba-ku, Sendai 980-8575, Japan.
Behav Brain Res. 2025 Jul 26;490:115617. doi: 10.1016/j.bbr.2025.115617. Epub 2025 May 17.
Neurodevelopment has a "sensitive period" during which the brain is highly sensitive to experience. In this study, we used maternal separation (MS) models of male Long-Evans rats to examine whether sensitivity to stress changes after postnatal day (PND) 10, when dendritic spine density begins to increase rapidly in the CA (Cornu Ammonis)1 region of the hippocampus. We assigned littermates to three groups: early maternal separation group (EMS: MS during PND 1-9), late maternal separation group (LMS: MS during PND 10-20), and control group. During adulthood (PND 56-75, which strictly corresponds to young adulthood), LMS showed increased depression-like behaviors and decreased dendritic spine density in the CA1 hippocampal region; however, EMS did not show any such changes. Accordingly, littermates at PND 10-20 have a greater vulnerability to MS than those at PND 1-9. These findings suggest that dendritic spine formation in the hippocampus is an important factor in determining sensitivity to MS.
神经发育存在一个“敏感期”，在此期间大脑对经验高度敏感。在本研究中，我们使用雄性长 Evans 大鼠的母婴分离（MS）模型，来检验出生后第 10 天（PND10）后应激敏感性是否发生变化，此时海马体 CA1（海马角）区域的树突棘密度开始迅速增加。我们将同窝幼崽分为三组：早期母婴分离组（EMS：PND1 - 9 期间进行 MS）、晚期母婴分离组（LMS：PND10 - 20 期间进行 MS）和对照组。在成年期（PND56 - 75，严格对应青年期），LMS 表现出类似抑郁的行为增加，海马体 CA1 区域的树突棘密度降低；然而，EMS 未表现出任何此类变化。因此，PND10 - 20 的同窝幼崽比 PND1 - 9 的同窝幼崽对 MS 更敏感。这些发现表明，海马体中树突棘的形成是决定对 MS 敏感性的一个重要因素。
