Itarat W, Jones D G
Department of Anatomy, University of Otago, Dunedin, New Zealand.
Synapse. 1992 Aug;11(4):279-86. doi: 10.1002/syn.890110403.
It has been known for some time that perforated synapses increase in number and size with increasing age. Initially, these trends were used to support the concept that nonperforated synapses enlarge until an optimal size is reached, at which point they perforate and may subsequently split. More recent stereological and three-dimensional reconstruction investigations, however, suggest that this may not be the case and that perforated and nonperforated synapses constitute separate synaptic populations. In order to test the separate population hypothesis, synapses have been studied ultrastructurally in the parietal cortex of rats aged 19 and 20 days gestation, and 1 and 4 days postnatal. By examining synapses serially, and also by studying three-dimensional reconstructions, it has been demonstrated that perforated synapses are present at each of these ages. Some are relatively simple in organization, resembling previously described perforated synapses at 14 days of age, although others appear to consist of two or more separate PSD components. These findings demonstrate that perforated synapses are present from early on in synaptogenesis and that developing perforated synapses may have distinct characteristics that cast light on their developmental course.
一段时间以来，人们已经知道，穿孔突触的数量和大小会随着年龄的增长而增加。最初，这些趋势被用来支持这样一种观点，即无穿孔突触会不断增大，直到达到最佳大小，此时它们会穿孔，随后可能会分裂。然而，最近的体视学和三维重建研究表明，情况可能并非如此，穿孔突触和无穿孔突触构成了不同的突触群体。为了验证不同群体假说，对妊娠19天和20天以及出生后1天和4天的大鼠顶叶皮质中的突触进行了超微结构研究。通过连续检查突触，并研究三维重建，已证实在这些年龄段的每一个都存在穿孔突触。有些在组织结构上相对简单，类似于之前描述的14日龄穿孔突触，尽管其他一些似乎由两个或更多个独立的突触后致密部（PSD）成分组成。这些发现表明，穿孔突触在突触发生早期就已存在，并且发育中的穿孔突触可能具有独特的特征，这有助于揭示它们的发育过程。
