J Physiol Editor in Chief
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH
QUICK SEARCH:   [advanced]


     

Physiology in Press

First published online on August 12, 2004.
 Copyright © 2004 by The Physiological Society
This Article
Right arrow Full Text (Rapid PDF)
Right arrow All Versions of this Article:
560/2/439    most recent
jphysiol.2004.066035v1
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow Author home page(s):
Felix E Schweizer
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Edmonds, B.
Right arrow Articles by Schweizer, F. E
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Edmonds, B.
Right arrow Articles by Schweizer, F. E

Received April 6, 2004
Revised May 19, 2004
Accepted after revision August 10, 2004

Evidence that fast exocytosis can be predominantly mediated by vesicles not docked at active zones in frog saccular hair cells

Brian Edmonds1, Frederick D Gregory1, and Felix E Schweizer1*

1 UCLA

* To whom correspondence should be addressed. E-mail: felixs{at}ucla.edu.

The prevailing model of neurotransmitter release stipulates that Ca2+ influx triggers the rapid fusion of vesicles that are docked at presynaptic active zones. Under this model, slower tonic release is supported by vesicles clustered nearby that have to translocate to the release sites before fusion. We have examined this hypothesis at the afferent synapse of saccular hair cells of the leopard frog, Rana pipiens. Detailed morphological measurements at this ribbon synapse show that on average 32 vesicles are docked at each active zone. We show that at this 'graded' synapse, depolarization produces an exocytotic "burst" that is largely complete within 20 ms after fusion of 280 vesicles per active zone, almost an order of magnitude more than expected. Recovery from paired pulse depression occurs with a time constant of 29 ms, indicating that replenishment of this fast fusing pool of vesicles is also fast. Our results suggest that non-docked vesicles are capable of fast fusion and that these vesicles constitute the vast majority of the fast-fusing pool. The view that the population of fast fusing presynaptic vesicles is limited to docked vesicles therefore requires reevaluation. We propose that compound fusion, i.e. the fusion of vesicles with each other before and/or after they fuse with the membrane can explain multi-vesicular release at this synapse.


Key words: Capacitance • Exocytosis • Hair Cell




This article has been cited by other articles:


Home page
 J. Neurophysiol.Home page
J. H. Wittig Jr and T. D. Parsons
Synaptic Ribbon Enables Temporal Precision of Hair Cell Afferent Synapse by Increasing the Number of Readily Releasable Vesicles: A Modeling Study
J Neurophysiol, October 1, 2008; 100(4): 1724 - 1739.
[Abstract] [Full Text] [PDF]

Home page
 J. Neurosci.Home page
M. Beurg, S. Safieddine, I. Roux, Y. Bouleau, C. Petit, and D. Dulon
Calcium- and Otoferlin-Dependent Exocytosis by Immature Outer Hair Cells
J. Neurosci., February 20, 2008; 28(8): 1798 - 1803.
[Abstract] [Full Text] [PDF]

Home page
 J. Physiol.Home page
R. Heidelberger
Mechanisms of tonic, graded release: lessons from the vertebrate photoreceptor
J. Physiol., December 15, 2007; 585(3): 663 - 667.
[Abstract] [Full Text] [PDF]

Home page
 J. Neurosci.Home page
A. Neef, D. Khimich, P. Pirih, D. Riedel, F. Wolf, and T. Moser
Probing the Mechanism of Exocytosis at the Hair Cell Ribbon Synapse
J. Neurosci., November 21, 2007; 27(47): 12933 - 12944.
[Abstract] [Full Text] [PDF]

Home page
 Proc. Natl. Acad. Sci. USAHome page
J. D. Goutman and E. Glowatzki
Time course and calcium dependence of transmitter release at a single ribbon synapse
PNAS, October 9, 2007; 104(41): 16341 - 16346.
[Abstract] [Full Text] [PDF]

Home page
 J. Neurophysiol.Home page
J. C. Holt, S. Chatlani, A. Lysakowski, and J. M. Goldberg
Quantal and Nonquantal Transmission in Calyx-Bearing Fibers of the Turtle Posterior Crista
J Neurophysiol, September 1, 2007; 98(3): 1083 - 1101.
[Abstract] [Full Text] [PDF]

Home page
 J. Physiol.Home page
T. Moser, A. Neef, and D. Khimich
Mechanisms underlying the temporal precision of sound coding at the inner hair cell ribbon synapse
J. Physiol., October 1, 2006; 576(1): 55 - 62.
[Abstract] [Full Text] [PDF]

Home page
 Proc. Natl. Acad. Sci. USAHome page
E. C. Keen and A. J. Hudspeth
Transfer characteristics of the hair cell's afferent synapse
PNAS, April 4, 2006; 103(14): 5537 - 5542.
[Abstract] [Full Text] [PDF]

Home page
 J. Neurosci.Home page
K. Rabl, L. Cadetti, and W. B. Thoreson
Paired-Pulse Depression at Photoreceptor Synapses
J. Neurosci., March 1, 2006; 26(9): 2555 - 2563.
[Abstract] [Full Text] [PDF]

Home page
 Proc. Natl. Acad. Sci. USAHome page
M. A. Rutherford and W. M. Roberts
Frequency selectivity of synaptic exocytosis in frog saccular hair cells
PNAS, February 21, 2006; 103(8): 2898 - 2903.
[Abstract] [Full Text] [PDF]

Home page
 J. Neurophysiol.Home page
J. C. Holt, J.-T. Xue, A. M. Brichta, and J. M. Goldberg
Transmission Between Type II Hair Cells and Bouton Afferents in the Turtle Posterior Crista
J Neurophysiol, January 1, 2006; 95(1): 428 - 452.
[Abstract] [Full Text] [PDF]

Home page
 Biophys. JHome page
S. Schein and K. M. Ahmad
A Clockwork Hypothesis: Synaptic Release by Rod Photoreceptors Must Be Regular
Biophys. J., December 1, 2005; 89(6): 3931 - 3949.
[Abstract] [Full Text] [PDF]


HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH
Copyright © 2004 The Physiological Society.