Jones D G, Harris R J
Department of Anatomy and Structural Biology, University of Otago, Dunedin, New Zealand.
Rev Neurosci. 1995 Jul-Sep;6(3):177-219. doi: 10.1515/revneuro.1995.6.3.177.
Perforated synapses refer to a synaptic type found in the central nervous system. They are characterized by their large size and by a discontinuity of the postsynaptic density when viewed in transverse sections, and by a doughnut or horseshoe shape when viewed in en face views. Of recent morphological studies, one approach has followed their characteristics throughout development and maturity, while others have concentrated on their probable roles in activities including kindling, long-term potentiation, spatial working memory, differential rearing, and the functioning of neuroleptics. An assessment is made of the hypotheses and models that have proved determinative in the emergence of perforated synapses as being significant in synaptic plasticity. Their distribution and frequency are summarized, with emphasis on the importance of unbiased stereological procedures in their analysis. Using three-dimensional approaches various subtypes are recognized. Of these, a complex or fragmented subtype appears of especial significance in synaptic plasticity. Ideas regarding the life-cycle of perforated synapses are examined. The view that they originate from conventional, non-perforated synapses, enlarge, and subsequently split to give rise to a new generation of non-perforated synapses, is critically assessed. According to an alternative model, perforated and non-perforated synapses constitute separate populations from early in their development, each representing complementary forms of synaptic plasticity. An attempt is also made to discover whether synaptic studies on the human brain in normal aging and in Alzheimer's disease throw light on the role of perforated synapses in synaptic plasticity. The loss of synapses in Alzheimer's disease may include a loss of perforated synapses - of particular relevance for an understanding of certain neuropathological conditions.
穿孔突触是指在中枢神经系统中发现的一种突触类型。其特点是尺寸较大，在横切面上观察时突触后致密部存在间断，在正面观察时呈甜甜圈或马蹄形。在最近的形态学研究中，一种方法是追踪它们在整个发育和成熟过程中的特征，而其他研究则集中于它们在包括点燃、长时程增强、空间工作记忆、差异饲养以及抗精神病药物作用等活动中可能发挥的作用。对那些已证明在穿孔突触出现过程中起决定性作用且对突触可塑性具有重要意义的假说和模型进行了评估。总结了它们的分布和频率，强调了无偏倚立体学方法在其分析中的重要性。使用三维方法识别出了各种亚型。其中，一种复杂或碎片化的亚型在突触可塑性方面似乎具有特别重要的意义。研究了关于穿孔突触生命周期的观点。那种认为它们起源于传统的非穿孔突触、扩大并随后分裂产生新一代非穿孔突触的观点受到了批判性评估。根据另一种模型，穿孔突触和非穿孔突触在发育早期就构成了不同的群体，各自代表突触可塑性的互补形式。还试图探究在正常衰老和阿尔茨海默病患者大脑中进行的突触研究是否能阐明穿孔突触在突触可塑性中的作用。阿尔茨海默病中突触的丧失可能包括穿孔突触的丧失——这对于理解某些神经病理状况尤为重要。
