Tarrant S B, Routtenberg A
Tissue Cell. 1977;9(3):461-73. doi: 10.1016/0040-8166(77)90006-4.
The present report calls attention to a component of certain synaptic junctions which has received little attention since its description in 1962 by Westrum and Blackstad. This component, which we term the synaptic spinule, is found in dendritic spine synapses in rat telencephalon (e.g., hippocampus, caudate nucleus, temporal and frontal cortex). Its major feature is an invagination of the presynaptic terminal by the presynaptic membrane, with the postsynaptic membrane protruding into this invagination. The synaptic spinule occurs in close association with the post-synaptic density, often occurring between breaks in this specialization. Serial sections reveal that when a synaptic spinule is present, a spine apparatus is observed near the dendritic protrusion. Coated vesicles are sometimes observed associated with the synaptic spinule; in all such instances they are associated with the presynaptic membrane. We studied the distribution of synaptic spinules in the dentate gyrus of the hippocampus. In contrast to its presence in the molecular layer, the synaptic spinule has not been observed in terminals of the subgranular layer of the dentate hilus. It is speculated that the synaptic spinule may play a role in exchange of material at dendritic spine synaptic junctions.
本报告提请注意某些突触连接的一个组成部分，自1962年韦斯特鲁姆和布莱克施塔德对其进行描述以来，该组成部分很少受到关注。这个组成部分，我们称之为突触小棘，见于大鼠端脑的树突棘突触（如海马体、尾状核、颞叶和额叶皮质）。其主要特征是突触前膜使突触前终末内陷，突触后膜突入此内陷中。突触小棘与突触后致密物紧密相关，常出现在这种特化结构的间断处之间。连续切片显示，当存在突触小棘时，在树突突起附近可观察到棘器。有时可观察到包被小泡与突触小棘相关；在所有这些情况下，它们都与突触前膜相关。我们研究了海马齿状回中突触小棘的分布。与在分子层中的存在情况相反，在齿状回门部颗粒下层的终末中未观察到突触小棘。据推测，突触小棘可能在树突棘突触连接处的物质交换中起作用。
