Department of Neurology, Affiliated ZhongDa Hospital and the Institution Neuropsychiatry of Southeast University, Nanjing, Jiangsu, China.
PLoS One. 2011;6(12):e28686. doi: 10.1371/journal.pone.0028686. Epub 2011 Dec 14.
It is generally accepted that cognitive processes, such as learning and memory, are affected in depression. The present study used a rat model of depression, chronic unpredictable mild stress (CUMS), to determine whether hippocampal volume and neurochemical changes were involved in learning and memory alterations. A further aim was to determine whether these effects could be ameliorated by escitalopram treatment, as assessed with the non-invasive techniques of structural magnetic resonance imaging (MRI) and magnetic resonance spectroscopy (MRS). Our results demonstrated that CUMS had a dramatic influence on spatial cognitive performance in the Morris water maze task, and CUMS reduced the concentration of neuronal marker N-acetylaspartate (NAA) in the hippocampus. These effects could be significantly reversed by repeated administration of escitalopram. However, neither chronic stress nor escitalopram treatment influenced hippocampal volume. Of note, the learning and memory alterations of the rats were associated with right hippocampal NAA concentration. Our results indicate that in depression, NAA may be a more sensitive measure of cognitive function than hippocampal volume.
普遍认为，认知过程（如学习和记忆）在抑郁症中受到影响。本研究使用慢性不可预测轻度应激（CUMS）大鼠模型，以确定海马体积和神经化学变化是否参与学习和记忆改变。进一步的目的是确定这些影响是否可以通过依地普仑治疗来改善，这是通过非侵入性技术结构磁共振成像（MRI）和磁共振波谱（MRS）来评估的。我们的研究结果表明，CUMS 对 Morris 水迷宫任务中的空间认知表现有显著影响，并且 CUMS 降低了海马体中神经元标志物 N-乙酰天冬氨酸（NAA）的浓度。依地普仑的重复给药可显著逆转这些影响。然而，慢性应激或依地普仑治疗均未影响海马体体积。值得注意的是，大鼠的学习和记忆改变与右海马体 NAA 浓度相关。我们的研究结果表明，在抑郁症中，NAA 可能是比海马体体积更敏感的认知功能测量指标。
