Kirk L M, Garcia G C, Hanka D C, Zatyko K, Bartol T, Sejnowski T J, Harris K M
Center for Learning and Memory, Department of Neuroscience, University of Texas at Austin, Austin, TX 78712.
Computational Neurobiology Laboratory, The Salk Institute for Biological Sciences, La Jolla, CA 92037.
bioRxiv. 2025 May 2:2025.04.29.651313. doi: 10.1101/2025.04.29.651313.
Long-term potentiation (LTP) induces presynaptic bouton enlargement and a reduction in the number of synaptic vesicles. To understand the relationship between these events, we performed 3D analysis of serial section electron micrographs in rat hippocampal area CA1, 2 hours after LTP induction. We observed a high vesicle packing density in control boutons, contrasting with a lower density in most LTP boutons. Notably, the summed membrane area of the vesicles lost in low-density LTP boutons is comparable to the surface membrane required for the observed bouton enlargement when compared to high-density control boutons. These novel findings suggest that presynaptic vesicle density provides a new structural indicator of LTP that supports a local mechanism of bouton enlargement.
长时程增强（LTP）会诱导突触前终扣增大以及突触小泡数量减少。为了理解这些事件之间的关系，我们在LTP诱导2小时后，对大鼠海马CA1区的连续切片电子显微照片进行了三维分析。我们观察到对照终扣中囊泡堆积密度较高，而大多数LTP终扣中的密度较低。值得注意的是，与高密度对照终扣相比，低密度LTP终扣中丢失的囊泡的总膜面积与观察到的终扣增大所需的表面膜面积相当。这些新发现表明，突触前囊泡密度为LTP提供了一种新的结构指标，支持终扣增大的局部机制。
