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bioRxiv · 10.1101/2025.04.29.651313

Presynaptic vesicles supply membrane for axonal bouton enlargement during LTP

Kirk, L. M.·Garcia, G. C.·Zatyko, K.·Bartol, T. M.·Sejnowski, T. J.·Harris, K. M.
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Abstract

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.

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Kirk, L. M., Garcia, G. C., Zatyko, K., Bartol, T. M., Sejnowski, T. J., Harris, K. M.. 2025-05-01. Presynaptic vesicles supply membrane for axonal bouton enlargement during LTP. https://doi.org/10.1101/2025.04.29.651313

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