A maximum of two readily releasable vesicles per docking site at a cerebellar single active zone synapse
Recent research suggests that in central mammalian synapses, active zones contain several docking sites acting in parallel. Before release, one or several synaptic vesicles (SVs) are thought to bind to each docking site, forming the readily releasable pool (RRP). Determining the RRP size per docking...
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| Format: | Article |
| Language: | English |
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eLife Sciences Publications Ltd
2024-01-01
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| Series: | eLife |
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| Online Access: | https://elifesciences.org/articles/91087 |
| _version_ | 1797245277730504704 |
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| author | Melissa Silva Van Tran Alain Marty |
| author_facet | Melissa Silva Van Tran Alain Marty |
| author_sort | Melissa Silva |
| collection | DOAJ |
| description | Recent research suggests that in central mammalian synapses, active zones contain several docking sites acting in parallel. Before release, one or several synaptic vesicles (SVs) are thought to bind to each docking site, forming the readily releasable pool (RRP). Determining the RRP size per docking site has important implications for short-term synaptic plasticity. Here, using mouse cerebellar slices, we take advantage of recently developed methods to count the number of released SVs at single glutamatergic synapses in response to trains of action potentials (APs). In each recording, the number of docking sites was determined by fitting with a binomial model the number of released SVs in response to individual APs. After normalization with respect to the number of docking sites, the summed number of released SVs following a train of APs was used to estimate of the RRP size per docking site. To improve this estimate, various steps were taken to maximize the release probability of docked SVs, the occupancy of docking sites, as well as the extent of synaptic depression. Under these conditions, the RRP size reached a maximum value close to two SVs per docking site. The results indicate that each docking site contains two distinct SV-binding sites that can simultaneously accommodate up to one SV each. They further suggest that under special experimental conditions, as both sites are close to full occupancy, a maximal RRP size of two SVs per docking site can be reached. More generally, the results validate a sequential two-step docking model previously proposed at this preparation. |
| first_indexed | 2024-03-08T16:37:20Z |
| format | Article |
| id | doaj.art-851b4db2534145c0be30dc060be3ba67 |
| institution | Directory Open Access Journal |
| issn | 2050-084X |
| language | English |
| last_indexed | 2024-04-24T19:24:21Z |
| publishDate | 2024-01-01 |
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| spelling | doaj.art-851b4db2534145c0be30dc060be3ba672024-03-25T16:17:42ZengeLife Sciences Publications LtdeLife2050-084X2024-01-011210.7554/eLife.91087A maximum of two readily releasable vesicles per docking site at a cerebellar single active zone synapseMelissa Silva0https://orcid.org/0000-0002-2687-8650Van Tran1https://orcid.org/0000-0002-3435-0258Alain Marty2https://orcid.org/0000-0001-6478-6880Université Paris Cité, SPPIN-Saints Pères Paris Institute for the Neurosciences, CNRS, Paris, FranceUniversité Paris Cité, SPPIN-Saints Pères Paris Institute for the Neurosciences, CNRS, Paris, FranceUniversité Paris Cité, SPPIN-Saints Pères Paris Institute for the Neurosciences, CNRS, Paris, FranceRecent research suggests that in central mammalian synapses, active zones contain several docking sites acting in parallel. Before release, one or several synaptic vesicles (SVs) are thought to bind to each docking site, forming the readily releasable pool (RRP). Determining the RRP size per docking site has important implications for short-term synaptic plasticity. Here, using mouse cerebellar slices, we take advantage of recently developed methods to count the number of released SVs at single glutamatergic synapses in response to trains of action potentials (APs). In each recording, the number of docking sites was determined by fitting with a binomial model the number of released SVs in response to individual APs. After normalization with respect to the number of docking sites, the summed number of released SVs following a train of APs was used to estimate of the RRP size per docking site. To improve this estimate, various steps were taken to maximize the release probability of docked SVs, the occupancy of docking sites, as well as the extent of synaptic depression. Under these conditions, the RRP size reached a maximum value close to two SVs per docking site. The results indicate that each docking site contains two distinct SV-binding sites that can simultaneously accommodate up to one SV each. They further suggest that under special experimental conditions, as both sites are close to full occupancy, a maximal RRP size of two SVs per docking site can be reached. More generally, the results validate a sequential two-step docking model previously proposed at this preparation.https://elifesciences.org/articles/91087synaptic terminalscerebellummolecular layer interneuronsparallel fiberssynaptic vesicles |
| spellingShingle | Melissa Silva Van Tran Alain Marty A maximum of two readily releasable vesicles per docking site at a cerebellar single active zone synapse eLife synaptic terminals cerebellum molecular layer interneurons parallel fibers synaptic vesicles |
| title | A maximum of two readily releasable vesicles per docking site at a cerebellar single active zone synapse |
| title_full | A maximum of two readily releasable vesicles per docking site at a cerebellar single active zone synapse |
| title_fullStr | A maximum of two readily releasable vesicles per docking site at a cerebellar single active zone synapse |
| title_full_unstemmed | A maximum of two readily releasable vesicles per docking site at a cerebellar single active zone synapse |
| title_short | A maximum of two readily releasable vesicles per docking site at a cerebellar single active zone synapse |
| title_sort | maximum of two readily releasable vesicles per docking site at a cerebellar single active zone synapse |
| topic | synaptic terminals cerebellum molecular layer interneurons parallel fibers synaptic vesicles |
| url | https://elifesciences.org/articles/91087 |
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