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Updated: Jan 4, 2026
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An Optical Assay for Synaptic Vesicle Recycling in Cultured Neurons Overexpressing Presynaptic Proteins
Published on: June 26, 2018
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Sparse force-bearing bridges between neighboring synaptic vesicles
John F Wesseling1,2, Sébastien Phan3, Eric A Bushong3
1Instituto de Neurociencias, CSIC-UMH, San Juan de Alicante, Spain. johnfwesseling@gmail.com.
Brain Structure & Function
|November 1, 2019
Summary
Vesicle bridges, stable structures in synaptic terminals, are less frequent in synapsin knockouts. This suggests synapsin proteins are crucial for forming or stabilizing these important synaptic vesicle connections.
Area of Science:
- Neuroscience
- Cell Biology
- Structural Biology
Background:
- Vesicles cluster near active zones in synaptic terminals for exocytosis.
- Electron-dense structures, termed bridges, are observed between some neighboring synaptic vesicles.
- The in vivo stability and existence of these vesicle bridges have been debated, with synapsin proteins previously implicated.
Purpose of the Study:
- To investigate the in vivo stability of synaptic vesicle bridges.
- To determine the role of synapsin proteins in the formation or stabilization of vesicle bridges.
Main Methods:
- Utilized electron tomography to visualize synaptic vesicle arrangements in wildtype and synapsin knockout mice.
- Analyzed the distances between neighboring vesicles in tomograms to assess bridge stability under experimental conditions.
Main Results:
- Synaptic vesicle bridges were found to be less frequent in synapsin knockout samples compared to wildtype.
- Analysis of vesicle neighbor distances in wildtype tomograms demonstrated that bridges can withstand centrifugal forces induced by aldehyde fixation, indicating stability.
- These findings confirm the presence of stable vesicle bridges in vivo.
Conclusions:
- Synaptic vesicle bridges are stable structures within synaptic terminals.
- Synapsin proteins play a significant role in the formation and/or stabilization of these synaptic vesicle bridges.
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