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Coordinated multivesicular release at a mammalian ribbon synapse
Joshua H Singer1, Luisa Lassová, Noga Vardi
1Synaptic Physiology Unit, NIH/NINDS, 36 Convent Drive, MSC-4066, Building 36 Room 2C-09, Bethesda, Maryland 20892, USA. singerj@ninds.nih.gov
Nature Neuroscience
|July 6, 2004
Summary
Coordination among release sites occurs during multivesicular release (MVR) at ribbon synapses. This finding challenges traditional models by suggesting synchronized vesicle release within active zones.
Area of Science:
- Neuroscience
- Cell Biology
- Synaptic Transmission
Background:
- Synaptic transmission models propose independent release sites within active zones.
- Multivesicular release (MVR) is known but not believed to require site coordination.
- The dynamics of MVR at ribbon synapses remain largely uncharacterized.
Purpose of the Study:
- To investigate the dynamics of multivesicular release (MVR) at a specific type of ribbon synapse.
- To determine if release sites within an active zone coordinate their activity during MVR.
Main Methods:
- Utilized paired recordings in a retinal slice preparation.
- Examined presynaptic rod bipolar cells and postsynaptic AII amacrine cells.
- Analyzed postsynaptic currents to infer vesicle release events.
Main Results:
- Observed postsynaptic events larger than quantal miniature excitatory postsynaptic currents (mEPSCs) but with identical time courses.
- These multiquantal events suggest near-simultaneous release of multiple vesicles.
- Event amplitude decreased with reduced release probability, indicating coordinated release.
Conclusions:
- Release within an active zone is coordinated during MVR at ribbon synapses.
- This coordination challenges the traditional view of independent release sites.
- Findings suggest a more complex mechanism for vesicle release at these synapses.