Shtrahman, Matthew
(2005)
Probing Vesicles Dynamics in Single Hippocampal Synapses.
Doctoral Dissertation, University of Pittsburgh.
(Unpublished)
Abstract
The classic mode of communication between neurons occurs via chemical synapses. In this process, vesicles dock at the active zone and fuse with the cell membrane, emptying neurotransmitter into the synaptic cleft. This process is stochastic and the efficacy of synaptic communication depends on the availability and movement of vesicles. We use fluorescence correlation spectroscopy (FCS) and fluorescence recovery after photobleaching (FRAP) to study vesicle dynamics inside the synapses of cultured hippocampal neurons labeled with the fluorescent vesicle marker FM 1-43. These studies show that when the cell is electrically at rest, only a small population of vesicles is mobile, taking seconds to traverse the synapse. Applying the phosphatase inhibitor okadaic acid (OA) causes vesicles to diffuse freely, moving 30 times faster than vesicles in control synapses. In contrast, eliminating polymerized synaptic actin does not free vesicles. These results suggest that vesicles move sluggishly due to binding to structural proteins within the synapse, and that this binding is altered by phosphorylation. Motivated by these results, a model is constructed consisting of diffusing vesicles that bind reversibly within the synapse. This stick-and-diffuse model accounts for the FCS and FRAP data, and also predicts the well-known exponential refilling of the readily releasable pool. Our measurements suggest that the movement of vesicles to the active zone is the rate limiting step in this process.
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Details
| Item Type: |
University of Pittsburgh ETD
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| Status: |
Unpublished |
| Creators/Authors: |
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| ETD Committee: |
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| Date: |
6 June 2005 |
| Date Type: |
Completion |
| Defense Date: |
28 March 2005 |
| Approval Date: |
6 June 2005 |
| Submission Date: |
18 April 2005 |
| Access Restriction: |
No restriction; Release the ETD for access worldwide immediately. |
| Institution: |
University of Pittsburgh |
| Schools and Programs: |
Dietrich School of Arts and Sciences > Physics |
| Degree: |
PhD - Doctor of Philosophy |
| Thesis Type: |
Doctoral Dissertation |
| Refereed: |
Yes |
| Uncontrolled Keywords: |
fluorescence correlation spectroscopy (FCS); fluorescence recovery after photobleaching (FRAP); FM 1-43; readily releasable pool; refilling; synaptic vesicle |
| Other ID: |
http://etd.library.pitt.edu/ETD/available/etd-04182005-160433/, etd-04182005-160433 |
| Date Deposited: |
10 Nov 2011 19:38 |
| Last Modified: |
15 Nov 2016 13:40 |
| URI: |
http://d-scholarship.pitt.edu/id/eprint/7275 |
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