Rapid and Long-Lasting Increase in Sites for Synapse Assembly during Late-Phase Potentiation in Rat Hippocampal Neurons
Rapid and Long-Lasting Increase in Sites for Synapse Assembly during Late-Phase Potentiation in Rat Hippocampal Neurons
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DOI：
10.1371/journal.pone.0007690
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发表时间：
2009-11-06
期刊：
影响因子：
3.7
通讯作者：
Hawkins, Robert D.
中科院分区：
文献类型：
--
作者：
Antonova, Irina;Lu, Fang-Min;Hawkins, Robert D.
海马神经元的长时程增强具有与学习和记忆阶段相对应的阶段。早期（10-30分钟）增强伴随着突触前和突触后蛋白质的簇或点的快速增加，其依赖于肌动蛋白聚合而不是蛋白质合成。我们现在已经研究了谷氨酸诱导的晚期（3小时）增强培养的海马神经元突触前和突触后斑点和结构的变化。我们发现：（1）这种增强作用伴随着长时间持续的点的增加，这取决于蛋白质的合成，（2）大多数点和突触结构是非常动态的，在比点或结构本身更稳定的位点上不断组装和分解，（3）突触前点的增加似乎是由于突触前点可能形成的部位数量的快速和更渐进的增加，以及现有点的稳定化，（4）在控制条件下，突触后蛋白质的点的行为与突触前蛋白质的点相似，并且与它们共享位点，和（5）突触前点的增加伴随着推测的突触前结构的类似增加，其可以在不同的以及共享的位点形成。这些新的位点可以作为新突触形成和维持的种子，从而在晚期可塑性过程中作为蛋白质合成依赖性突触生长的局部“标签”，从而有助于可塑性早期和晚期机制之间的过渡。
Long-term potentiation in hippocampal neurons has stages that correspond to the stages of learning and memory. Early-phase (10-30 min) potentiation is accompanied by rapid increases in clusters or puncta of presynaptic and postsynaptic proteins, which depend on actin polymerization but not on protein synthesis. We have now examined changes in pre- and postsynaptic puncta and structures during glutamate-induced late-phase ( 3 hr) potentiation in cultured hippocampal neurons. We find that ( 1) the potentiation is accompanied by long-lasting maintenance of the increases in puncta, which depends on protein synthesis, ( 2) most of the puncta and synaptic structures are very dynamic, continually assembling and disassembling at sites that are more stable than the puncta or structures themselves, ( 3) the increase in presynaptic puncta appears to be due to both rapid and more gradual increases in the number of sites where the puncta may form, and also to the stabilization of existing puncta, ( 4) under control conditions, puncta of postsynaptic proteins behave similarly to puncta of presynaptic proteins and share sites with them, and ( 5) the increase in presynaptic puncta is accompanied by a similar increase in presumably presynaptic structures, which may form at distinct as well as shared sites. The new sites could contribute to the transition between the early and late phase mechanisms of plasticity by serving as seeds for the formation and maintenance of new synapses, thus acting as local "tags'' for protein synthesis-dependent synaptic growth during late-phase plasticity.