Synaptic Potentiation Induces Increased Glial Coverage of Excitatory Synapses in CA1 Hippocampus
Synaptic Potentiation Induces Increased Glial Coverage of Excitatory Synapses in CA1 Hippocampus
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DOI：
10.1002/hipo.20551
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发表时间：
2009-01-01
期刊：
影响因子：
3.5
通讯作者：
Nikonenko, Irina
中科院分区：
文献类型：
--
作者：
Lushnikova, Irina;Skibo, Galina;Nikonenko, Irina
在兴奋性突触处诱导突触可塑性的活动模式（例如长时程增强）会导致突触后棘的结构重塑，包括棘头的扩大和突触后密度（PSD）的重组。此外，棘突触代表了复杂的功能单位，其中突触前静脉曲张和突触后棘之间的相互作用也受到周围星形胶质细胞过程的调节。为了研究活动模式如何影响这三个合作伙伴之间的形态相互作用，我们使用了电子显微镜（EM）的方法和兴奋性突触的三维重建，研究活动相关的形态学变化的基础诱导突触增强θ爆发刺激或短暂的氧/葡萄糖剥夺发作海马器官型切片文化。EM分析表明，在体内大鼠海马中描述的典型的胶质突触组织是完美的保存和可比的器官型切片培养。三维重建的突触，分为简单或复杂的PSD组织，表现出显着的变化后，使用这两种协议的突触增强诱导。刺激后30 min和1 h，脊髓头部体积和PSD面积显著增大，特别是在具有复杂PSD的大突触中，这种效应与突触前末梢的伴随增大相关。此外，突触活动诱导的前和突触后结构的神经胶质覆盖的显着增加，这些变化被阻止通过应用的NMDA受体拮抗剂D-2-氨基-5-phosphonopentanoic酸。这些数据揭示了动态的，活性依赖性的相互作用之间的神经胶质细胞的过程和突触前和突触后的合作伙伴，并表明，神经胶质细胞可以参与活动诱导的结构性突触重塑。(C)2009威利-利斯公司
Patterns of activity that induce synaptic plasticity at excitatory synapses, such as long-term potentiation, result in structural remodeling of the postsynaptic spine, comprising an enlargement of the spine head and reorganization of the postsynaptic density (PSD). Furthermore, spine synapses represent complex functional units in which interaction between the presynaptic varicosity and the postsynaptic spine is also modulated by surrounding astroglial processes. To investigate how activity patterns could affect the morphological interplay between these three partners, we used an electron microscopic (EM) approach and 3D reconstructions of excitatory synapses to study the activity-related morphological changes underlying induction of synaptic potentiation by theta burst stimulation or brief oxygen/glucose deprivation episodes in hippocampal organotypic slice cultures. EM analyses demonstrated that the typical glia-synapse organization described in in vivo rat hippocampus is perfectly preserved and comparable in organotypic slice cultures. Three-dimensional reconstructions of synapses, classified as simple or complex depending upon PSD organization, showed significant changes following induction of synaptic potentiation using both protocols. The spine head volume and the area of the PSD significantly enlarged 30 min and 1 h after stimulation, particularly in large synapses with complex PSD, an effect that was associated with a concomitant enlargement of presynaptic terminals. Furthermore, synaptic activity induced a pronounced increase of the glial coverage of both pre- and postsynaptic structures, these changes being prevented by application of the NMDA receptor antagonist D-2-amino-5-phosphonopentanoic acid. These data reveal dynamic, activity-dependent interactions between glial processes and pre- and postsynaptic partners and suggest that glia can participate in activity-induced structural synapse remodeling. (C) 2009 Wiley-Liss, Inc.