Novelty exposure overcomes foot shock-induced spatial-memory impairment by processes of synaptic-tagging in rats
Novelty exposure overcomes foot shock-induced spatial-memory impairment by processes of synaptic-tagging in rats
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DOI：
10.1073/pnas.1114198109
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发表时间：
2012-01-17
影响因子：
11.1
通讯作者：
Frey, Julietta U.
中科院分区：
文献类型：
--
作者：
Almaguer-Melian, William;Bergado-Rosado, Jorge;Frey, Julietta U.
新颖性加工可以将短期记忆转化为长期记忆。我们提出，这种新颖性的记忆强化效应可以用“突触标记假说”中概述的机制来解释。最初的短期记忆是通过激活突触的短暂可塑性变化来维持的，并设置突触标签。这些标签随后能够捕获和处理可塑性相关蛋白（PRPs），这是将短期突触变化转化为长期突触变化所必需的。新颖性参与诱导PRPs合成[Moncada D， et al. (2011) Proc Natl Acad Sci USA 108: 12937-12936]，这些PRPs随后被标记的突触捕获，巩固记忆。与新奇相反，压力会损害学习、记忆和突触的可塑性。在这里，我们解决的问题是，新奇诱导的PRPs是否能够防止由压力引起的记忆丧失，如果后者不会与标签设置过程相互作用。我们使用水迷宫（WM）训练作为空间学习范式来检验我们的假设。在WM训练后5分钟施加足部强休克（FS; 5 × 1 mA, 2 s）诱导应激。我们的数据显示，在WM范式中，FS减少了长期记忆，但没有减少短期记忆。这种对记忆巩固的负面影响与时间和训练有关。有趣的是，接触新奇事物可以防止空间任务中压力引起的记忆丧失，并增加BDNF和Arc的表达。这种修复作用被大霉素阻断，这表明wm标记的突触没有被FS重置，因此能够捕获新奇诱导的prp，重建FS受损的长期记忆。
Novelty processing can transform short-term into long-term memory. We propose that this memory-reinforcing effect of novelty could be explained by mechanisms outlined in the "synaptic tagging hypothesis." Initial short-term memory is sustained by a transient plasticity change at activated synapses and sets synaptic tags. These tags are later able to capture and process the plasticity-related proteins (PRPs), which are required to transform a short-term synaptic change into a long-term one. Novelty is involved in inducing the synthesis of PRPs [Moncada D, et al. (2011) Proc Natl Acad Sci USA 108: 12937-12936], which are then captured by the tagged synapses, consolidating memory. In contrast to novelty, stress can impair learning, memory, and synaptic plasticity. Here, we address questions as to whether novelty-induced PRPs are able to prevent the loss of memory caused by stress and if the latter would not interact with the tag-setting process. We used water-maze (WM) training as a spatial learning paradigm to test our hypothesis. Stress was induced by a strong foot shock (FS; 5 x 1 mA, 2 s) applied 5 min after WM training. Our data show that FS reduced long-term but not short-term memory in the WM paradigm. This negative effect on memory consolidation was time- and training-dependent. Interestingly, novelty exposure prevented the stress-induced memory loss of the spatial task and increased BDNF and Arc expression. This rescuing effect was blocked by anisomycin, suggesting that WM-tagged synapses were not reset by FS and were thus able to capture the novelty-induced PRPs, reestablishing FS-impaired long-term memory.