Center for Psychiatric Neuroscience, Department of Psychiatry, Prilly.
Exp Biol Med (Maywood). 2012 Nov;237(11):1331-40. doi: 10.1258/ebm.2012.012020.
In the present work we studied synaptic protein concentrations in relation to behavioral performance. Long-Evans rats, aged 22-23 months, were classified for individual expression of place memory in the Morris water maze, in reference to young adults. Two main subgroups of aged rats were established: the Aged cognitively Unimpaired (AU) had search accuracy within the range (percent of time in training sector within mean ± 2 SEM) of young rats and the Aged cognitively Impaired (AI) rats had search accuracy below this range. Samples from the hippocampus and frontal cortex of all the AI, AU and young rats were analyzed for the expression of postsynaptic protein PSD-95 by Image J analysis of immunohistochemical data and by Western blots. PSD-95 expression was unchanged in the hippocampus, but, together with synaptophysin, was significantly increased in the frontal cortex of the AI rats. A significant correlation between individual accuracy (time spent in the training zone) and PSD-95 expression was observed in the aged group. No significant effect of age or PSD-95 expression was observed in the learning of a new position. All together, these data suggest that increased expression of PSD-95 in the frontal cortex of aged rats co-occurs with cognitive impairment that might be linked to functional alterations extending over frontal networks.
在本工作中，我们研究了突触蛋白浓度与行为表现的关系。22-23 月龄的长耳大仓鼠，根据其在 Morris 水迷宫中位置记忆的个体表现进行分类，以与年轻成年动物进行比较。确定了两组主要的老年大鼠亚组：认知无障碍的老年（AU）大鼠的搜索准确率在（训练阶段时间百分比，在均值±2 个 SEM 范围内）与年轻大鼠的范围之内，而认知受损的老年（AI）大鼠的搜索准确率低于这个范围。对所有 AI、AU 和年轻大鼠的海马体和前额皮质样本进行 PSD-95 后突触蛋白表达的分析，通过免疫组织化学数据的 Image J 分析和 Western blot 进行分析。在海马体中 PSD-95 的表达没有改变，但是，与突触小泡蛋白一起，AI 大鼠的前额皮质中的表达显著增加。在老年组中观察到个体准确性（在训练区的时间）与 PSD-95 表达之间存在显著相关性。在学习新位置时，年龄或 PSD-95 表达没有显著影响。综上所述，这些数据表明，前额皮质中 PSD-95 的表达增加与认知障碍同时发生，这可能与扩展到额网络的功能改变有关。
