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Readily releasable pool of synaptic vesicles measured at single synaptic contacts.

ABSTRACT: To distinguish between different models of vesicular release in brain synapses, it is necessary to know the number of vesicles of transmitter that can be released immediately at individual synapses by a high-calcium stimulus, the readily releasable pool (RRP). We used direct stimulation by calcium uncaging at identified, single-site inhibitory synapses to investigate the statistics of vesicular release and the size of the RRP. Vesicular release, detected as quantal responses in the postsynaptic neuron, showed an unexpected stochastic variation in the number of quanta from stimulus to stimulus at high intracellular calcium, with a mean of 1.9 per stimulus and a maximum of three or four. The results provide direct measurement of the RRP at single synaptic sites. They are consistent with models in which release proceeds from a small number of vesicle docking sites with an average occupancy around 0.7.

SUBMITTER: Trigo FF

PROVIDER: S-EPMC3497746 | biostudies-literature | 2012 Oct

REPOSITORIES: biostudies-literature

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Readily releasable pool of synaptic vesicles measured at single synaptic contacts.

Trigo Federico F FF Sakaba Takeshi T Ogden David D Marty Alain A

Proceedings of the National Academy of Sciences of the United States of America 20121016 44

To distinguish between different models of vesicular release in brain synapses, it is necessary to know the number of vesicles of transmitter that can be released immediately at individual synapses by a high-calcium stimulus, the readily releasable pool (RRP). We used direct stimulation by calcium uncaging at identified, single-site inhibitory synapses to investigate the statistics of vesicular release and the size of the RRP. Vesicular release, detected as quantal responses in the postsynaptic ...[more]

PMID: 23074252

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