scholarly journals Release of the Styryl Dyes from Single Synaptic Vesicles in Hippocampal Neurons

2008 ◽  
Vol 28 (8) ◽  
pp. 1894-1903 ◽  
Author(s):  
X. Chen ◽  
S. Barg ◽  
W. Almers
Keyword(s):  
Synaptic Vesicles ◽  
Hippocampal Neurons ◽  
Styryl Dyes

scholarly journals BDNF mobilizes synaptic vesicles and enhances synapse formation by disrupting cadherin–β-catenin interactions

2006 ◽  
Vol 174 (2) ◽  
pp. 289-299 ◽  
Author(s):  
Shernaz X. Bamji ◽  
Beatriz Rico ◽  
Nikole Kimes ◽  
Louis F. Reichardt
Keyword(s):  
Synaptic Vesicle ◽  
Synaptic Vesicles ◽  
Hippocampal Neurons ◽  
Molecular Mechanisms ◽  
Synapse Formation ◽  
Time Lapse ◽  
Synapse Density ◽  
Vesicle Mobility ◽  
Small Clusters ◽  
Vertebrate Central Nervous System

Neurons of the vertebrate central nervous system have the capacity to modify synapse number, morphology, and efficacy in response to activity. Some of these functions can be attributed to activity-induced synthesis and secretion of the neurotrophin brain-derived neurotrophic factor (BDNF); however, the molecular mechanisms by which BDNF mediates these events are still not well understood. Using time-lapse confocal analysis, we show that BDNF mobilizes synaptic vesicles at existing synapses, resulting in small clusters of synaptic vesicles “splitting” away from synaptic sites. We demonstrate that BDNF's ability to mobilize synaptic vesicle clusters depends on the dissociation of cadherin–β-catenin adhesion complexes that occurs after tyrosine phosphorylation of β-catenin. Artificially maintaining cadherin–β-catenin complexes in the presence of BDNF abolishes the BDNF-mediated enhancement of synaptic vesicle mobility, as well as the longer-term BDNF-mediated increase in synapse number. Together, this data demonstrates that the disruption of cadherin–β-catenin complexes is an important molecular event through which BDNF increases synapse density in cultured hippocampal neurons.

A Simple Depletion Model of the Readily Releasable Pool of Synaptic Vesicles Cannot Account for Paired-Pulse Depression

2007 ◽  
Vol 97 (1) ◽  
pp. 948-950 ◽  
Author(s):  
Jane M. Sullivan
Keyword(s):  
Synaptic Vesicles ◽  
Hippocampal Neurons ◽  
Synaptic Activity ◽  
Excitatory Synapses ◽  
Short Term ◽  
Paired Pulse ◽  
Short Term Plasticity ◽  
Releasable Pool ◽  
Readily Releasable Pool ◽  
Paired Pulse Depression

Paired-pulse depression (PPD) is a form of short-term plasticity that plays a central role in processing of synaptic activity and is manifest as a decrease in the size of the response to the second of two closely timed stimuli. Despite mounting evidence to the contrary, PPD is still commonly thought to reflect depletion of the pool of synaptic vesicles available for release in response to the second stimulus. Here it is shown that PPD cannot be accounted for by depletion at excitatory synapses made by hippocampal neurons because PPD is unaffected by changes in the fraction of the readily releasable pool (RRP) released by the first of a pair of pulses.

Optical Mesurements of Presynaptic Function: What Keeps Vesicle Traffic Going

1998 ◽  
Vol 4 (S2) ◽  
pp. 1020-1021
Author(s):  
Timothy A. Ryan
Keyword(s):  
Nervous System ◽  
Synaptic Vesicles ◽  
Hippocampal Neurons ◽  
Brain Cells ◽  
Membrane Recycling ◽  
Large Collection ◽  
Vesicle Traffic ◽  
Presynaptic Function ◽  
Average Total Number ◽  
Chemical Synapses

The nervous system has evolved to make use of a variety of mechanisms that allow information to flow and be processed among a large collection of individual cells. The communication between individual brain cells occurs largely at chemical synapses. In these compartments, chemical messengers are packaged into small vesicles that fuse with the cell membrane upon stimulation, releasing neurotransmitter.. The average total number of synaptic vesicles in a typical central nervous system synapse is only a few hundred and as a result an efficient local recycling mechanism operates in order to replenish this pool during periods of even modest neuronal activity. Without this membrane recycling, synapses quickly become depleted of vesicles, and soon fail to communicate information between cells.We make use of optical techniques to follow the trafficking of synaptic vesicles at synapses formed between hippocampal neurons grown in culture. Recycling synaptic vesicles can be readily labeled using the fluorescent amphipathic membrane dye FM 1-43.

scholarly journals Determinants of synaptic strength vary across an axon arbor

2012 ◽  
Vol 107 (9) ◽  
pp. 2430-2441 ◽  
Author(s):  
Xiaoyu Peng ◽  
Thomas D. Parsons ◽  
Rita J. Balice-Gordon
Keyword(s):  
Synaptic Vesicles ◽  
Hippocampal Neurons ◽  
Synaptic Strength ◽  
Pool Size ◽  
Spatial Modulation ◽  
Readily Releasable Pool ◽  
Single Axon ◽  
Individual Vesicle ◽  
Highly Correlated ◽  
Vesicle Pool

We used synaptophysin-pHluorin expressed in hippocampal neurons to address how functional properties of terminals, namely, evoked release, total vesicle pool size, and release fraction, vary spatially across individual axon arbors. Consistent with previous reports, over short arbor distances (∼100 μm), evoked release was spatially heterogeneous when terminals contacted different postsynaptic dendrites or neurons. Regardless of the postsynaptic configuration, the evoked release and total vesicle pool size spatially covaried, suggesting that the fraction of synaptic vesicles available for release (release fraction) was similar over short distances. Evoked release and total vesicle pool size were highly correlated with the amount of NMDA receptors and PSD-95 in postsynaptic specialization. However, when individual axons were followed over longer distances (several hundred micrometers), a significant increase in evoked release was observed distally that was associated with an increased release fraction in distal terminals. The increase in distal release fraction can be accounted for by changes in individual vesicle release probability as well as readily releasable pool size. Our results suggest that for a single axon arbor, presynaptic strength indicated by evoked release over short distances is correlated with heterogeneity in total vesicle pool size, whereas over longer distances presynaptic strength is correlated with the spatial modulation of release fraction. Thus the mechanisms that determine synaptic strength differ depending on spatial scale.

scholarly journals Semi-automated analysis of an optical ATP indicator in neural synapses

2021 ◽  
Author(s):  
Taher Dehkharghanian ◽  
Arsalan Hashemiaghdam ◽  
Ghazaleh Ashrafi
Keyword(s):  
Synaptic Vesicles ◽  
Hippocampal Neurons ◽  
Quantitative Measurement ◽  
Automated Analysis ◽  
Automated Image Analysis ◽  
Subcellular Targeting ◽  
Biological Assays ◽  
Manual Analysis ◽  
Wide Range

AbstractSince its discovery in fireflies, bioluminescence has been used in a wide range of biological assays, from reporter gene assays to in vivo imaging. Bioluminescent light is produced from the enzymatic action of luciferase on its substrate luciferin using ATP as a cofactor. Recently, subcellular targeting of luciferase to neural synaptic vesicles has led to the development of the sensor Syn-ATP that allows for quantitative measurement of presynaptic ATP levels. Manual analysis of presynaptic bioluminescence signals from Syn-ATP is challenging due to signal heterogeneity and cellular motion in long imaging sessions. Here, we present a pipeline for semi-automated image analysis of Syn-ATP signals in the nerve terminals of hippocampal neurons. Our method streamlines data analysis and reduces user-introduced bias, thus enhancing the reproducibility and reliability of quantitative ATP imaging.

scholarly journals The synaptic vesicle cycle: a single vesicle budding step involving clathrin and dynamin.

1996 ◽  
Vol 133 (6) ◽  
pp. 1237-1250 ◽  
Author(s):  
K Takei ◽  
O Mundigl ◽  
L Daniell ◽  
P De Camilli
Keyword(s):  
Plasma Membrane ◽  
Synaptic Vesicle ◽  
Synaptic Vesicles ◽  
Hippocampal Neurons ◽  
Coated Vesicles ◽  
Coated Vesicle ◽  
Nerve Terminals ◽  
Vesicle Budding ◽  
Vesicle Cycle ◽  
Single Vesicle

Strong evidence implicates clathrin-coated vesicles and endosome-like vacuoles in the reformation of synaptic vesicles after exocytosis, and it is generally assumed that these vacuoles represent a traffic station downstream from clathrin-coated vesicles. To gain insight into the mechanisms of synaptic vesicle budding from endosome-like intermediates, lysed nerve terminals and nerve terminal membrane subfractions were examined by EM after incubations with GTP gamma S. Numerous clathrin-coated budding intermediates that were positive for AP2 and AP180 immunoreactivity and often collared by a dynamin ring were seen. These were present not only on the plasma membrane (Takei, K., P.S. McPherson, S.L.Schmid, and P. De Camilli. 1995. Nature (Lond.). 374:186-190), but also on internal vacuoles. The lumen of these vacuoles retained extracellular tracers and was therefore functionally segregated from the extracellular medium, although narrow connections between their membranes and the plasmalemma were sometimes visible by serial sectioning. Similar observations were made in intact cultured hippocampal neurons exposed to high K+ stimulation. Coated vesicle buds were generally in the same size range of synaptic vesicles and positive for the synaptic vesicle protein synaptotagmin. Based on these results, we suggest that endosome-like intermediates of nerve terminals originate by bulk uptake of the plasma membrane and that clathrin- and dynamin-mediated budding takes place in parallel from the plasmalemma and from these internal membranes. We propose a synaptic vesicle recycling model that involves a single vesicle budding step mediated by clathrin and dynamin.

scholarly journals Dynamics of synaptic vesicles of cultured hippocampal neurons

1995 ◽  
Vol 67 ◽  
pp. 12
Author(s):  
Tetsuhiro Tsujimoto ◽  
Charles F Stevens
Keyword(s):  
Synaptic Vesicles ◽  
Hippocampal Neurons ◽  
Cultured Hippocampal Neurons

scholarly journals Synaptophysin I Controls the Targeting of VAMP2/Synaptobrevin II to Synaptic Vesicles

2003 ◽  
Vol 14 (12) ◽  
pp. 4909-4919 ◽  
Author(s):  
Maria Pennuto ◽  
Dario Bonanomi ◽  
Fabio Benfenati ◽  
Flavia Valtorta
Keyword(s):  
Plasma Membrane ◽  
Membrane Protein ◽  
Synaptic Vesicle ◽  
Cell Body ◽  
Synaptic Vesicles ◽  
Hippocampal Neurons ◽  
Direct Interaction ◽  
Diffuse Component ◽  
Synaptotagmin I ◽  
Dose Dependent

Synaptic vesicle (SV) proteins are synthesized at the level of the cell body and transported down the axon in membrane precursors of SVs. To investigate the mechanisms underlying sorting of proteins to SVs, fluorescent chimeras of vesicle-associated membrane protein (VAMP) 2, its highly homologous isoform VAMP1 and synaptotagmin I (SytI) were expressed in hippocampal neurons in culture. Interestingly, the proteins displayed a diffuse component of distribution along the axon. In addition, VAMP2 was found to travel in vesicles that constitutively fuse with the plasma membrane. Coexpression of VAMP2 with synaptophysin I (SypI), a major resident of SVs, restored the correct sorting of VAMP2 to SVs. The effect of SypI on VAMP2 sorting was dose dependent, being reversed by increasing VAMP2 expression levels, and highly specific, because the sorting of the SV proteins VAMP1 and SytI was not affected by SypI. The cytoplasmic domain of VAMP2 was found to be necessary for both the formation of VAMP2-SypI hetero-dimers and for VAMP2 sorting to SVs. These data support a role for SypI in directing the correct sorting of VAMP2 in neurons and demonstrate that a direct interaction between the two proteins is required for SypI in order to exert its effect.

scholarly journals RNA editing of CAPS1 regulates synaptic vesicle organization, release and retrieval

2017 ◽  
Author(s):  
Randi J. Ulbricht ◽  
Sarah J. Sun ◽  
Claire E. DelBove ◽  
Kristina E. Kitko ◽  
Saad C. Rehman ◽  
...  
Keyword(s):  
Rna Editing ◽  
Neurotransmitter Release ◽  
Synaptic Vesicles ◽  
Hippocampal Neurons ◽  
Protein Isoforms ◽  
Editing Event ◽  
Calcium Dependent ◽  
Presynaptic Vesicle ◽  
Vesicle Pool ◽  
Fine Tune

ABSTRACTCalcium-dependent activator protein for secretion 1 (CAPS1) facilitates the docking and priming of synaptic and dense core vesicles. A conserved hairpin structure in the CAPS1 pre-mRNA allows an post-transcriptional adenosine-to-inosine RNA editing event to alter a genomically-encoded glutamate to a glycine codon. Functional comparisons of CAPS1 protein isoforms in primary hippocampal neurons show that elevation of edited CAPS1 isoforms facilitates presynaptic vesicle clustering and turnover. Conversely, non-edited CAPS1 isoforms slow evoked release, increase spontaneous fusion, and loosen the clustering of synaptic vesicles. Therefore, CAPS1 editing promotes organization of the vesicle pool in a way that is beneficial for evoked release, while non-edited isoforms promote more lax vesicle organization that widens distribution, attenuates evoked release and eases the control of spontaneous fusion. Overall, RNA editing of CAPS1 is a mechanism to fine tune neurotransmitter release.IMPACT STATEMENTPost-transcriptional RNA editing of CAPS1 is a mechanism to regulate neurotransmitter release from synaptic vesicles.

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