Comparing 3D ultrastructure of presynaptic and postsynaptic mitochondria
Comparing 3D ultrastructure of presynaptic and postsynaptic mitochondria
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DOI：
10.1242/bio.044834
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发表时间：
2019-08-01
期刊：
影响因子：
2.4
通讯作者：
Yao, Pamela J.
中科院分区：
文献类型：
--
作者：
Delgado, Thomas;Petralia, Ronald S.;Yao, Pamela J.
FIB-SEM（聚焦离子束扫描电子显微镜）等连续切片电子显微镜已成为神经科学家追踪大脑神经回路的轨迹和整体结构以及可视化神经元细胞器的 3D 超微结构的重要工具。在这项研究中，我们检查了小鼠大脑四个区域的连续切片生成的电子显微镜图像中线粒体的 3D 特征：伏隔核 (NA)、海马 CA1、体感皮层和耳蜗背核 (DCN)。我们将突触前末梢中的线粒体与突触后/树突室中的线粒体进行了比较，我们重点关注线粒体的形状和大小。四个脑区线粒体的一个共同特征是突触前线粒体一般较小且较短，并且大多数不延伸超出突触前末梢。相比之下，大多数突触后/树突线粒体很大，并且其中许多分布在树突的重要部分。比较大脑区域，大脑皮层和DCN的突触后/树突状线粒体比NA和CA1更大。我们的分析表明，神经元中的线粒体根据其亚细胞位置而具有不同的大小和排列，这表明突触处线粒体的空间组织原则。
Serial-section electron microscopy such as FIB-SEM (focused ion beam scanning electron microscopy) has become an important tool for neuroscientists to trace the trajectories and global architecture of neural circuits in the brain, as well as to visualize the 3D ultrastructure of cellular organelles in neurons. In this study, we examined 3D features of mitochondria in electron microscope images generated from serial sections of four regions of mouse brains: nucleus accumbens (NA), hippocampal CA1, somatosensory cortex and dorsal cochlear nucleus (DCN). We compared mitochondria in the presynaptic terminals to those in the postsynaptic/dendritic compartments, and we focused on the shape and size of mitochondria. A common feature of mitochondria among the four brain regions is that presynaptic mitochondria generally are small and short, and most of them do not extend beyond presynaptic terminals. In contrast, the majority of postsynaptic/dendritic mitochondria are large and many of them spread through significant portions of the dendrites. Comparing among the brain areas, the cerebral cortex and DCN have even larger postsynaptic/dendritic mitochondria than the NA and CA1. Our analysis reveals that mitochondria in neurons are differentially sized and arranged according to their subcellular locations, suggesting a spatial organizing principle of mitochondria at the synapse.