Single-vesicle imaging reveals that synaptic vesicle exocytosis and endocytosis are coupled by a single stochastic mode
- J. Balaji and
- T. A. Ryan*
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Edited by Francisco Bezanilla, University of Chicago, Chicago, IL, and approved November 6, 2007 (received for review August 10, 2007)
Abstract
The nature of synaptic vesicle recycling at nerve terminals has been a subject of considerable debate for >35 years. Here, we report the use of an optical strategy that allows the exocytosis and retrieval of synaptic components to be tracked in real time at single-molecule sensitivity in living nerve terminals. This approach has allowed us to examine the recycling of synaptic vesicles in response to single action potentials. Our results show that, after exocytosis, individual synaptic vesicles are retrieved by a stochastic process with an exponential distribution of delay times, with a mean time of ≈14 s. We propose that evidence for fast endocytosis, such as that proposed to support the presence of kiss-and-run, is likely explained by the stochastic nature of a slower process.
Footnotes
- *To whom correspondence should be addressed. E-mail: taryan{at}med.cornell.edu
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Author contributions: J.B. and T.A.R. designed research; J.B. performed research; J.B. and T.A.R. analyzed data; and J.B. and T.A.R. wrote the paper.
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The authors declare no conflict of interest.
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This article is a PNAS Direct Submission.
- © 2007 by The National Academy of Sciences of the USA
