Send to

Choose Destination
Proc Natl Acad Sci U S A. 2012 Oct 30;109(44):18138-43. doi: 10.1073/pnas.1209798109. Epub 2012 Oct 16.

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

Author information

Laboratoire de Physiologie Cérébrale, Centre National de la Recherche Scientifique and Université Paris Descartes, 75006 Paris, France.


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.

[Indexed for MEDLINE]
Free PMC Article

Supplemental Content

Full text links

Icon for HighWire Icon for PubMed Central
Loading ...
Support Center