2014
DOI: 10.1016/j.neuron.2014.08.003
|View full text |Cite
|
Sign up to set email alerts
|

Uniquantal Release through a Dynamic Fusion Pore Is a Candidate Mechanism of Hair Cell Exocytosis

Abstract: The mechanisms underlying the large amplitudes and heterogeneity of excitatory postsynaptic currents (EPSCs) at inner hair cell (IHC) ribbon synapses are unknown. Based on electrophysiology, electron and superresolution light microscopy, and modeling, we propose that uniquantal exocytosis shaped by a dynamic fusion pore is a candidate neurotransmitter release mechanism in IHCs. Modeling indicated that the extended postsynaptic AMPA receptor clusters enable large uniquantal EPSCs. Recorded multiphasic EPSCs wer… Show more

Help me understand this report

Search citation statements

Order By: Relevance

Paper Sections

Select...
2
2
1

Citation Types

11
179
1
1

Year Published

2015
2015
2022
2022

Publication Types

Select...
6
1
1

Relationship

2
6

Authors

Journals

citations
Cited by 94 publications
(196 citation statements)
references
References 70 publications
11
179
1
1
Order By: Relevance
“…Unlike conventional synapses that require action potentials to release vesicles, the presynaptic cells at many primary sensory synapses typically operate via graded membrane potential changes that can last several seconds. Here, vesicles are often tethered to a specialized protein structure called a ribbon that is thought to maintain and synchronize the release of hundreds of vesicles per second [8689, 16 but see, 90]. For example, at retinal bipolar cell terminals a 200 ms depolarization can release ~6000 synaptic vesicles at 50 synaptic ribbon release sites, with each ribbon releasing ~120 vesicles, a number similar to the total number of docked vesicles at the ribbon plus those tethered to the ribbon [91].…”
Section: Functions Of Mvr Throughout the Brainmentioning
confidence: 99%
See 1 more Smart Citation
“…Unlike conventional synapses that require action potentials to release vesicles, the presynaptic cells at many primary sensory synapses typically operate via graded membrane potential changes that can last several seconds. Here, vesicles are often tethered to a specialized protein structure called a ribbon that is thought to maintain and synchronize the release of hundreds of vesicles per second [8689, 16 but see, 90]. For example, at retinal bipolar cell terminals a 200 ms depolarization can release ~6000 synaptic vesicles at 50 synaptic ribbon release sites, with each ribbon releasing ~120 vesicles, a number similar to the total number of docked vesicles at the ribbon plus those tethered to the ribbon [91].…”
Section: Functions Of Mvr Throughout the Brainmentioning
confidence: 99%
“…Several hypotheses have been proposed to explain the nearsynchronous fusion of several tens of vesicles, including coordination of release sites and tight coupling of calcium channels to the release machinery [89, 96, 21], fusion of several vesicles to each other prior to exocytosis (compound fusion [97]). Recently, however, fusion pore regulation of UVR events has been proposed as an alternate mechanism to explain multiphasic EPSCs [90]. …”
Section: Functions Of Mvr Throughout the Brainmentioning
confidence: 99%
“…Recently, uniquantal release through a dynamic fusion pore has been suggested as an alternative hypothesis for IHC synapses of rodents 76 . The motivation came from considering the spike rates of hundreds of hertz over prolonged periods of time, which, according to the multiquantal hypothesis (on average, six vesicles per EPSC 59 ), would require at least sixfold-higher vesicle release rates, which seem very high considering measured rates of sustained exocytosis of about 700 vesicles per second 27 .…”
Section: Large and Variable Excitatory Postsynaptic Currents: The Unimentioning
confidence: 99%
“…Moreover, multiphasic (less synchronized) and monophasic (synchronized) events were observed (Glowatzki and Fuchs, 2002). Recently, an alternative release mechanism has been suggested (Chapochnikov et al, 2014) that builds on the assumption that a single vesicle can release sufficient amounts of glutamate to generate the measured large EPSCs. In the framework of this hypothesis, the observed heterogeneity of EPSC amplitudes and shape is explained by post-fusion control via a dynamic fusion pore.…”
Section: Different Synapse Types Mediate Sound Encodingmentioning
confidence: 99%
“…This spatial characteristic ensures an instant reception of released glutamate upon stimulation. The flickering of a dynamic fusion pore releasing only portions of a single vesicle's content would cause multiphasic EPSCs (Chapochnikov et al, 2014). It is left to speculation whether both mechanisms co-exist at IHC ribbon synapses or are mutually exclusive.…”
Section: Different Synapse Types Mediate Sound Encodingmentioning
confidence: 99%