Induction and activity-dependent reversal of persistent LTP and LTD in lateral perforant path synapses in vivo
Induction and activity-dependent reversal of persistent LTP and LTD in lateral perforant path synapses in vivo
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DOI：
10.1016/j.nlm.2005.12.007
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发表时间：
2006-07-01
影响因子：
2.7
通讯作者：
Gill, AI
中科院分区：
文献类型：
--
作者：
Abraham, WC;Mason-Parker, SE;Gill, AI
在自由活动的成年Sprague-Dawley大鼠的外侧穿支通路上，观察了长时程增强（LTP）和异突触长时程抑制（LTD）的可逆性。持续数周的LTP在几分钟内迅速逆转的高频异突触刺激的内侧穿通路径，在N-甲基-D-天冬氨酸受体依赖的方式。当动物在富集环境（EE）中过夜1-3周时，也会发生LTP逆转，尽管速度更慢且程度更小。LTD同样在重复EE暴露后逆转。当考虑到EE处理本身对侧向路径反应的小增强效应时，LTP和LTD逆转程度之间的隐蔽相似性被揭示出来。尽管EE能够逆转先前获得的突触可塑性，但两周的EE治疗对动物在空间水迷宫任务中保持平台位置没有影响，尽管它确实促进了新的学习。这些数据是在协议的假设，海马突触保持快速突触变化的能力，即使在其他相对稳定的可塑性先前已被诱导。这种可塑性的缓慢逆转与记忆保持的丧失无关，这可能是因为缓慢的变化允许重组表征，以便新旧信息都可以容纳，或者新信息以正交的方式与旧信息进行突触表征。(c)2005年爱思唯尔公司All rights reserved.
The reversibility of long-term potentiation (LTP) and heterosynaptic long-term depression (LTD) lasting weeks was examined in the lateral perforant path of freely moving adult Sprague-Dawley rats. LTP lasting weeks was rapidly reversed within minutes by high-frequency heterosynaptic stimulation of the medial perforant path, in an N-methyl-D-aspartate receptor-dependent manner. LTP reversal also occurred, albeit more slowly and to a lesser extent, when animals were given 1-3 weeks of overnight exposure to an enriched environment (EE). LTD likewise was reversed upon repeated EE exposure. A covert similarity between the degrees of LTP and LTD reversal was revealed when the small potentiation effect of EE treatment by itself on lateral path responses was taken into account. Despite its ability to reverse previously acquired synaptic plasticity, two weeks of EE treatment had no effect on animals' retention of the platform location in a spatial watermaze task, although it did facilitate new learning. These data are in agreement with the hypothesis that hippocampal synapses retain the capacity for rapid synaptic change even when otherwise relatively stable plasticity has previously been induced. Slow reversal of such plasticity did not correlate with a loss of memory retention, possibly because either slow changes permit reorganization of representations such that both old and new information can be accommodated, or else the new information is synaptically represented in orthogonal fashion to the old information. (c) 2005 Elsevier Inc. All rights reserved.