New ways of looking at synapses
New ways of looking at synapses
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DOI：
10.1007/s00418-007-0305-7
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发表时间：
2007-08-01
影响因子：
2.3
通讯作者：
Studer, Daniel
中科院分区：
文献类型：
--
作者：
Frotscher, Michael;Zhao, Shanting;Studer, Daniel
目前突触精细结构的概念源于对使用醛的化学固定的组织的电子显微镜研究。然而，用戊二醛和多聚甲醛进行化学固定，然后在乙醇中脱水，会导致组织无法控制的收缩。虽然电子显微镜可以明确地识别突触接触，但它不能用于实时分析突触的结构变化。对于后一种目的，将应用先进的荧光显微镜技术，但不允许识别突触接触。在这里，描述了两种方法，它们至少部分地克服了突触研究中的一些缺陷。通过聚焦于一种特征的、容易识别的突触--海马区的苔藓纤维突触，我们首先描述了高压冷冻新鲜组织的方法，该方法可以用于研究与功能突触可塑性相关的突触超微结构的细微变化。接下来，我们建议用不同的荧光染料标记CA3锥体神经元上的突触前苔藓纤维终末和突触后复合棘，以便在更长的时间内实时监测活组织中的这些突触。我们希望这些方法能为中枢突触的结构和功能带来新的见解。
Current concepts of synaptic fine-structure are derived from electron microscopic studies of tissue fixed by chemical fixation using aldehydes. However, chemical fixation with glutaraldehyde and paraformaldehyde and subsequent dehydration in ethanol result in uncontrolled tissue shrinkage. While electron microscopy allows for the unequivocal identification of synaptic contacts, it cannot be used for real-time analysis of structural changes at synapses. For the latter purpose advanced fluorescence microscopy techniques are to be applied which, however, do not allow for the identification of synaptic contacts. Here, two approaches are described that may overcome, at least in part, some of these drawbacks in the study of synapses. By focusing on a characteristic, easily identifiable synapse, the mossy fiber synapse in the hippocampus, we first describe high-pressure freezing of fresh tissue as a method that may be applied to study subtle changes in synaptic ultrastructure associated with functional synaptic plasticity. Next, we propose to label presynaptic mossy fiber terminals and postsynaptic complex spines on CA3 pyramidal neurons by different fluorescent dyes to allow for the real-time monitoring of these synapses in living tissue over extended periods of time. We expect these approaches to lead to new insights into the structure and function of central synapses.