scholarly journals Probing synaptic vesicle fusion by altering mechanical properties of the neuronal surface membrane

2008 ◽  
Vol 105 (46) ◽  
pp. 18018-18022 ◽  
Author(s):  
Yongling Zhu ◽  
Charles F. Stevens
Keyword(s):  
Mechanical Properties ◽  
Synaptic Vesicle ◽  
Surface Membrane ◽  
Fusion Pore ◽  
Neuronal Membrane ◽  
Mechanical Process ◽  
Synaptic Vesicle Exocytosis ◽  
Fusion Probability ◽  
Vesicle Exocytosis ◽  
Synaptic Vesicle Fusion

Because synaptic vesicle exocytosis is a nano-mechanical process, it should be influenced by the mechanical properties of the cell membrane to which the vesicle fuses. By dissolving surfactants at various concentrations in the neuronal membrane, we have perturbed mechanical properties of the membrane and have found that dissolved surfactants lower the probability that a synaptic vesicle will open its fusion pore when the fusion machinery of the vesicle is activated by binding calcium. By using standard theories from the physics and chemistry of surfaces, we can account for this decrease in fusion probability and can infer that a vesicle, when activated, opens its fusion pore ≈3 times out of 4 and that the area of the fusion pore is ≈4 nm2.

scholarly journals Insulin signaling controls neurotransmission via the 4eBP-dependent modification of the exocytotic machinery

eLife ◽  
2016 ◽  
Vol 5 ◽  
Author(s):  
Rebekah Elizabeth Mahoney ◽  
Jorge Azpurua ◽  
Benjamin A Eaton
Keyword(s):  
Synaptic Vesicle ◽  
Insulin Signaling ◽  
Regulatory Mechanism ◽  
Neuronal Function ◽  
Cellular Mechanisms ◽  
Genetic Manipulations ◽  
Synaptic Vesicle Exocytosis ◽  
Vesicle Exocytosis ◽  
Dependent Modification ◽  
Synaptic Vesicle Fusion

Altered insulin signaling has been linked to widespread nervous system dysfunction including cognitive dysfunction, neuropathy and susceptibility to neurodegenerative disease. However, knowledge of the cellular mechanisms underlying the effects of insulin on neuronal function is incomplete. Here, we show that cell autonomous insulin signaling within the Drosophila CM9 motor neuron regulates the release of neurotransmitter via alteration of the synaptic vesicle fusion machinery. This effect of insulin utilizes the FOXO-dependent regulation of the thor gene, which encodes the Drosophila homologue of the eif-4e binding protein (4eBP). A critical target of this regulatory mechanism is Complexin, a synaptic protein known to regulate synaptic vesicle exocytosis. We find that the amounts of Complexin protein observed at the synapse is regulated by insulin and genetic manipulations of Complexin levels support the model that increased synaptic Complexin reduces neurotransmission in response to insulin signaling.

scholarly journals A continuum model of docking of synaptic vesicle to plasma membrane

2015 ◽  
Vol 12 (102) ◽  
pp. 20141119 ◽  
Author(s):  
Tianshu Liu ◽  
Pankaj Singh ◽  
James T. Jenkins ◽  
Anand Jagota ◽  
Maria Bykhovskaia ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Synaptic Vesicle ◽  
Neurotransmitter Release ◽  
Pore Formation ◽  
Continuum Model ◽  
Synaptic Cleft ◽  
Fusion Pore ◽  
Neuronal Membrane ◽  
Electrostatic Repulsion ◽  
Synaptic Vesicle Fusion

Neurotransmitter release from neuronal terminals is governed by synaptic vesicle fusion. Vesicles filled with transmitters are docked at the neuronal membrane by means of the SNARE machinery. After a series of events leading up to the fusion pore formation, neurotransmitters are released into the synaptic cleft. In this paper, we study the mechanics of the docking process. A continuum model is used to determine the deformation of a spherical vesicle and a plasma membrane, under the influence of SNARE-machinery forces and electrostatic repulsion. Our analysis provides information on the variation of in-plane stress in the membranes, which is known to affect fusion. Also, a simple model is proposed to study hemifusion.

scholarly journals Role of specific presynaptic calcium channel subtypes in isoflurane inhibition of synaptic vesicle exocytosis in rat hippocampal neurones

2019 ◽  
Vol 123 (2) ◽  
pp. 219-227 ◽  
Author(s):  
Yuko Koyanagi ◽  
Christina L. Torturo ◽  
Daniel C. Cook ◽  
Zhenyu Zhou ◽  
Hugh C. Hemmings
Keyword(s):  
Calcium Channel ◽  
Synaptic Vesicle ◽  
Synaptic Vesicle Exocytosis ◽  
Vesicle Exocytosis ◽  
Presynaptic Calcium

scholarly journals SNARE Complex Oligomerization by Synaphin/Complexin Is Essential for Synaptic Vesicle Exocytosis

Cell ◽  
2001 ◽  
Vol 104 (3) ◽  
pp. 421-432 ◽  
Author(s):  
Hiroshi Tokumaru ◽  
Keiko Umayahara ◽  
Lorenzo L Pellegrini ◽  
Toru Ishizuka ◽  
Hideo Saisu ◽  
...  
Keyword(s):  
Synaptic Vesicle ◽  
Snare Complex ◽  
Synaptic Vesicle Exocytosis ◽  
Vesicle Exocytosis

scholarly journals Diurnal Changes in Exocytosis and the Number of Synaptic Ribbons at Active Zones of an on-Type Bipolar Cell Terminal

2006 ◽  
Vol 96 (4) ◽  
pp. 2025-2033 ◽  
Author(s):  
Court Hull ◽  
Keith Studholme ◽  
Stephen Yazulla ◽  
Henrique von Gersdorff
Keyword(s):  
Synaptic Vesicle ◽  
Bipolar Cell ◽  
Bipolar Cells ◽  
Synaptic Ribbons ◽  
Diurnal Changes ◽  
Synaptic Vesicle Exocytosis ◽  
Pulse Ratio ◽  
Vesicle Exocytosis ◽  
Active Zones ◽  
Vesicle Pool

The number and morphology of synaptic ribbons at photoreceptor and bipolar cell terminals has been reported to change on a circadian cycle. Here we sought to determine whether this phenomenon exists at goldfish Mb-type bipolar cell terminals with the aim of exploring the role of ribbons in transmitter release. We examined the physiology and ultrastructure of this terminal around two time points: midday and midnight. Nystatin perforated-patch recordings of membrane capacitance ( Cm) revealed that synaptic vesicle exocytosis evoked by short depolarizations was reduced at night, even though Ca2+ currents were larger. The efficiency of exocytosis (measured as the Δ Cm jump per total Ca2+ charge influx) was thus significantly lower at night. The paired-pulse ratio remained unchanged, however, suggesting that release probability was not altered. Hence the decreased exocytosis likely reflects a smaller readily releasable vesicle pool at night. Electron microscopy of single sections from intact retinas averaged 65% fewer ribbons at night. Interestingly, the number of active zones did not change from day to night, only the probability of finding a ribbon at an active zone. Additionally, synaptic vesicle halos surrounding the ribbons were more completely filled at night when these on-type bipolar cells are more hyperpolarized. There was no change, however, in the physical dimensions of synaptic ribbons from day to night. These results suggest that the size of the readily releasable vesicle pool and the efficiency of exocytosis are reduced at night when fewer ribbons are present at bipolar cell terminal active zones.

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