Variance-mean analysis in the presence of a rapid antagonist indicates vesicle depletion underlies depression at the climbing fiber synapse.

Full Abstract

Many types of synapses throughout the nervous system are transiently depressed during high-frequency stimulation. Several mechanisms have been proposed to account for this depression, including depletion of release-ready vesicles. However, numerous studies have raised doubts about the importance of depletion in depression of central synapses and have implicated alternative mechanisms, such as decreased release probability. We use variance-mean analysis to determine the mechanism of depression at the climbing fiber to Purkinje cell synapse. We find that postsynaptic receptor saturation makes it difficult to distinguish between a decrease in available vesicles and a reduction in release probability. When AMPA receptor saturation is relieved with a low-affinity antagonist, variance-mean analysis reveals that depression arises from a decrease in the number of release-ready vesicles. Vesicle depletion is prominent, despite numerous docked vesicles at each release site, due to multivesicular release. We conclude that vesicle depletion can contribute significantly to depression of central synapses.

Author information

Author/s: Foster, Kelly A (KA); Regehr, Wade G (WG);

Affiliation: Department of Neurobiology, Harvard Medical School, Boston, MA 02115, USA.

Grants: R01-NS432405 (Agency:NINDS NIH HHS)

Journal and publication information

Publication Type: Journal Article; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, P.H.S.

Journal: Neuron (Neuron), published in United States. (Language: eng)

Reference: 2004-Jul; vol 43 (issue 1) : pp 119-31

Dates: Created 2004/07/05; Completed 2004/08/26; Revised 2008/11/21;

PMID: 15233922, status: MEDLINE (last retrieval date: 2/18/2009, IMS Date: )

Sourced from the National Library of Medicine. Abstract text and other information may be subject to copyright.

External Links for this article
(including full text providers, if available):

Click Electronic Full-text Provider Links to see options for finding the electronic full text links to this article. Note there may be a subscription or fee required for access to the full text. See our FAQ for information on finding FREE full text articles.

This article may also be located in paper journal collections available in many libraries. Use the Journal and Publication Information above to find the full article.