Maxwell D J, Ottersen O P, Storm-Mathisen J
Laboratory of Human Anatomy, University of Glasgow, UK.
Brain Res. 1995 Apr 3;676(1):103-12. doi: 10.1016/0006-8993(95)00096-9.
The cell bodies and proximal dendrites of postsynaptic dorsal column neurons were examined for synaptic boutons which displayed immunoreactivity for the principal excitatory and inhibitory neurotransmitters, glutamate and GABA. The neurons were labelled by retrograde transport of horseradish peroxidase and GABA or glutamate-containing boutons were revealed by performing postembedding immunogold reactions on electron microscope sections. Five neurons were examined and all of them were postsynaptic to boutons which contained either GABA or glutamate. Quantitative analysis of two of the cells revealed that more than 90% of the synaptic profiles associated with them displayed immunogold reactions for these transmitters. Analysis of series of alternate sections, which were reacted for either GABA or glutamate, showed that there was no overlap in the populations of immunoreactive boutons. Furthermore, GABA and glutamate immunoreactions were associated with boutons which had different morphological characteristics. In addition, some large glutamate-enriched boutons were postsynaptic to small boutons which displayed immunogold reactions for GABA. This study demonstrates morphological bases for direct excitation, postsynaptic inhibition and presynaptic inhibition of postsynaptic dorsal column cells.
对突触后背柱神经元的细胞体和近端树突进行检查，以寻找对主要兴奋性和抑制性神经递质谷氨酸和γ-氨基丁酸（GABA）呈现免疫反应性的突触小体。通过辣根过氧化物酶的逆行运输标记神经元，并通过在电子显微镜切片上进行包埋后免疫金反应来显示含GABA或谷氨酸的突触小体。检查了5个神经元，所有这些神经元均与含有GABA或谷氨酸的突触小体形成突触后联系。对其中两个细胞的定量分析表明，与它们相关的超过90%的突触形态对这些神经递质呈现免疫金反应。对分别针对GABA或谷氨酸进行反应的一系列交替切片的分析表明，免疫反应性突触小体群体之间没有重叠。此外，GABA和谷氨酸免疫反应与具有不同形态特征的突触小体相关。此外，一些富含谷氨酸的大突触小体是对显示GABA免疫金反应的小突触小体的突触后成分。这项研究证明了突触后背柱细胞直接兴奋、突触后抑制和突触前抑制的形态学基础。
