scholarly journals Stimulation of Ca2+-dependent neurotransmitter release and presynaptic nerve terminal protein phosphorylation by calmodulin and a calmodulin-like protein isolated from synaptic vesicles

1979 ◽  
Vol 76 (4) ◽  
pp. 1838-1842 ◽  
Author(s):  
R. J. Delorenzo ◽  
S. D. Freedman ◽  
W. B. Yohe ◽  
S. C. Maurer
Keyword(s):  
Protein Phosphorylation ◽  
Nerve Terminal ◽  
Neurotransmitter Release ◽  
Synaptic Vesicles ◽  
Terminal Protein ◽  
Presynaptic Nerve Terminal ◽  
Stimulation Of

scholarly journals Neurotransmitter Secretion along Growing Nerve Processes: Comparison with Synaptic Vesicle Exocytosis

1999 ◽  
Vol 144 (3) ◽  
pp. 507-518 ◽  
Author(s):  
Stanislav Zakharenko ◽  
Sunghoe Chang ◽  
Michael O'Donoghue ◽  
Sergey V. Popov
Keyword(s):  
Nerve Terminal ◽  
Neurotransmitter Release ◽  
Synaptic Vesicles ◽  
High Frequency Stimulation ◽  
Spinal Cord Neurons ◽  
Presynaptic Nerve Terminal ◽  
Neurotransmitter Secretion ◽  
Synaptic Vesicle Exocytosis ◽  
Vesicle Exocytosis ◽  
Membrane Components

In mature neurons, synaptic vesicles continuously recycle within the presynaptic nerve terminal. In developing axons which are free of contact with a postsynaptic target, constitutive membrane recycling is not localized to the nerve terminal; instead, plasma membrane components undergo cycles of exoendocytosis throughout the whole axonal surface (Matteoli et al., 1992; Kraszewski et al., 1995). Moreover, in growing Xenopus spinal cord neurons in culture, acetylcholine (ACh) is spontaneously secreted in the quantal fashion along the axonal shaft (Evers et al., 1989; Antonov et al., 1998). Here we demonstrate that in Xenopus neurons ACh secretion is mediated by vesicles which recycle locally within the axon. Similar to neurotransmitter release at the presynaptic nerve terminal, ACh secretion along the axon could be elicited by the action potential or by hypertonic solutions. We found that the parameters of neurotransmitter secretion at the nerve terminal and at the middle axon were strikingly similar. These results lead us to conclude that, as in the case of the presynaptic nerve terminal, synaptic vesicles involved in neurotransmitter release along the axon contain a complement of proteins for vesicle docking and Ca2+-dependent fusion. Taken together, our results support the idea that, in developing axons, the rudimentary machinery for quantal neurotransmitter secretion is distributed throughout the whole axonal surface. Maturation of this machinery in the process of synaptic development would improve the fidelity of synaptic transmission during high-frequency stimulation of the presynaptic cell.

scholarly journals Botulinum Neurotoxin a Blocks Synaptic Vesicle Exocytosis but Not Endocytosis at the Nerve Terminal

1999 ◽  
Vol 147 (6) ◽  
pp. 1249-1260 ◽  
Author(s):  
Elaine A. Neale ◽  
Linda M. Bowers ◽  
Min Jia ◽  
Karen E. Bateman ◽  
Lura C. Williamson
Keyword(s):  
Synaptic Vesicle ◽  
Nerve Terminal ◽  
Neurotransmitter Release ◽  
Synaptic Vesicles ◽  
Botulinum Neurotoxin ◽  
Vesicle Membrane ◽  
Botulinum Neurotoxin A ◽  
Synaptic Vesicle Exocytosis ◽  
Vesicle Exocytosis ◽  
Botulinum Neurotoxins

The supply of synaptic vesicles in the nerve terminal is maintained by a temporally linked balance of exo- and endocytosis. Tetanus and botulinum neurotoxins block neurotransmitter release by the enzymatic cleavage of proteins identified as critical for synaptic vesicle exocytosis. We show here that botulinum neurotoxin A is unique in that the toxin-induced block in exocytosis does not arrest vesicle membrane endocytosis. In the murine spinal cord, cell cultures exposed to botulinum neurotoxin A, neither K+-evoked neurotransmitter release nor synaptic currents can be detected, twice the ordinary number of synaptic vesicles are docked at the synaptic active zone, and its protein substrate is cleaved, which is similar to observations with tetanus and other botulinal neurotoxins. In marked contrast, K+ depolarization, in the presence of Ca2+, triggers the endocytosis of the vesicle membrane in botulinum neurotoxin A–blocked cultures as evidenced by FM1-43 staining of synaptic terminals and uptake of HRP into synaptic vesicles. These experiments are the first demonstration that botulinum neurotoxin A uncouples vesicle exo- from endocytosis, and provide evidence that Ca2+ is required for synaptic vesicle membrane retrieval.

scholarly journals Postsynaptic Neuroligin-1 Mediates Presynaptic Endocytosis During Neuronal Activity

2021 ◽  
Vol 14 ◽  
Author(s):  
Jiaqi Keith Luo ◽  
Holly Melland ◽  
Jess Nithianantharajah ◽  
Sarah L. Gordon
Keyword(s):  
Ampa Receptors ◽  
Neurotransmitter Release ◽  
Synaptic Vesicles ◽  
High Fidelity ◽  
Excitatory Synapses ◽  
Synaptic Efficacy ◽  
Molecular Architecture ◽  
Adhesion Protein ◽  
Presynaptic Nerve Terminal ◽  
Presynaptic Release

Fast, high-fidelity neurotransmission and synaptic efficacy requires tightly regulated coordination of pre- and postsynaptic compartments and alignment of presynaptic release sites with postsynaptic receptor nanodomains. Neuroligin-1 (Nlgn1) is a postsynaptic cell-adhesion protein exclusively localised to excitatory synapses that is crucial for coordinating the transsynaptic alignment of presynaptic release sites with postsynaptic AMPA receptors as well as postsynaptic transmission and plasticity. However, little is understood about whether the postsynaptic machinery can mediate the molecular architecture and activity of the presynaptic nerve terminal, and thus it remains unclear whether there are presynaptic contributions to Nlgn1-dependent control of signalling and plasticity. Here, we employed a presynaptic reporter of neurotransmitter release and synaptic vesicle dynamics, synaptophysin-pHluorin (sypHy), to directly assess the presynaptic impact of loss of Nlgn1. We show that lack of Nlgn1 had no effect on the size of the readily releasable or entire recycling pool of synaptic vesicles, nor did it impact exocytosis. However, we observed significant changes in the retrieval of synaptic vesicles by compensatory endocytosis, specifically during activity. Our data extends growing evidence that synaptic adhesion molecules critical for forming transsynaptic scaffolds are also important for regulating activity-induced endocytosis at the presynapse.

Regulation of synaptic vesicles pools within motor nerve terminals during short-term facilitation and neuromodulation

2006 ◽  
Vol 100 (2) ◽  
pp. 662-671 ◽  
Author(s):  
S. Logsdon ◽  
A. F. M. Johnstone ◽  
K. Viele ◽  
R. L. Cooper
Keyword(s):  
Electrical Stimulation ◽  
Nerve Terminal ◽  
Synaptic Vesicles ◽  
Motor Nerve ◽  
Glutamate Transporter ◽  
Excitatory Postsynaptic Potential ◽  
Nerve Terminals ◽  
Presynaptic Nerve Terminal ◽  
Continuous Stimulation ◽  
Significant Difference

The reserve pool (RP) and readily releasable pool (RRP) of synaptic vesicles within presynaptic nerve terminals were physiologically differentiated into distinctly separate functional groups. This was accomplished in glutamatergic nerve terminals by blocking the glutamate transporter with dl-threo-β-benzyloxyaspartate (TBOA; 10 μM) during electrical stimulation with either 40 Hz of 10 pulses within a train or 20- or 50-Hz continuous stimulation. The 50-Hz continuous stimulation decreased the excitatory postsynaptic potential amplitude 60 min faster than for the 20-Hz continuous stimulation in the presence of TBOA ( P < 0.05). There was no significant difference between the train stimulation and 20-Hz continuous stimulation in the run-down time in the presence of TBOA. After TBOA-induced synaptic depression, the excitatory postsynaptic potentials were rapidly (<1 min) revitalized by exposure to serotonin (5-HT, 1 μM) in every preparation tested ( P < 0.05). At this glutamatergic nerve terminal, 5-HT promotes an increase probability of vesicular docking and fusion. Quantal recordings made directly at nerve terminals revealed smaller quantal sizes with TBOA exposure with a marked increase in quantal size as well as a continual appearance of smaller quanta upon 5-HT treatment after TBOA-induced depression. Thus 5-HT was able to recruit vesicles from the RP that were not rapidly depleted by acute TBOA treatment and electrical stimulation. The results support the notion that the RRP is selectively activated during rapid electrical stimulation sparing the RP; however, the RP can be recruited by the neuromodulator 5-HT. This suggests at least two separate kinetic and distinct regulatory paths for vesicle recycling within the presynaptic nerve terminal.

scholarly journals Multitude of ion channels in regulation of transmitter release

1999 ◽  
Vol 354 (1381) ◽  
pp. 281-288 ◽  
Author(s):  
Rami Rahamimoff ◽  
Alexander Butkevich ◽  
Dessislava Duridanova ◽  
Ronit Ahdut ◽  
Emanuel Harari ◽  
...  
Keyword(s):  
Ion Channels ◽  
Potassium Channels ◽  
Nerve Terminal ◽  
Transmitter Release ◽  
Synaptic Vesicles ◽  
Chloride Channels ◽  
Surface Membrane ◽  
Structural Basis ◽  
Primary Role ◽  
Presynaptic Nerve Terminal

The presynaptic nerve terminal is of key importance in the communication in the nervous system. Its primary role is to release transmitter quanta on the arrival of an appropriate stimulus. The structural basis of these transmitter quanta are the synaptic vesicles that fuse with the surface membrane of the nerve terminal, to release their content of neurotransmitter molecules and other vesicular components. We subdivide the control of quantal release into two major classes: the processes that take place before the fusion of the synaptic vesicle with the surface membrane (the pre–fusion control) and the processes that occur after the fusion of the vesicle (the post–fusion control). The pre–fusion control is the main determinant of transmitter release. It is achieved by a wide variety of cellular components, among them the ion channels. There are reports of several hundred different ion channel molecules at the surface membrane of the nerve terminal, that for convenience can be grouped into eight major categories. They are the voltage–dependent calcium channels, the potassium channels, the calcium–gated potassium channels, the sodium channels, the chloride channels, the non–selective channels, the ligand gated channels and the stretch–activated channels. There are several categories of intracellular channels in the mitochondria, endoplasmic reticulum and the synaptic vesicles. We speculate that the vesicle channels may be of an importance in the post–fusion control of transmitter release.

A structural study of the squid synapse after intraaxonal injection of calcium

1978 ◽  
Vol 201 (1145) ◽  
pp. 317-333 ◽  
Keyword(s):  
Electron Microscopy ◽  
Nerve Terminal ◽  
Synaptic Vesicles ◽  
Presynaptic Terminal ◽  
Presynaptic Membrane ◽  
Ground Structure ◽  
Presynaptic Nerve Terminal ◽  
Dense Deposits ◽  
Membrane Bound ◽  
Giant Synapse

The giant synapse of the squid was examined by electron microscopy after ionophoretic injection of Ca 2+ ions into the pre- or postsynaptic axon. The results suggest that there are differences in the Ca-buffering mechanisms in pre- and postsynaptic axons. For instance, after injection of Ca 2+ into the postsynaptic axon, mitochondria were heavily loaded with granular inclusions. In contrast, mitochondria of injected presynaptic terminals did not contain inclusions. In the postsynaptic axon, besides inclusions in mitochondria, dense deposits were found in axoplasmic vesicles and cisterns that appeared locally at the site of injection. Injection of Ca 2+ into the presynaptic terminal produced non-membrane bound dense deposits associated with the filamentous ground structure of the axoplasm. Some calcium may also be bound to the presynaptic membrane which appears dense after injection. In both axons the alterations produced by injected Ca 2+ were confined mainly to the area of injection. After injection of Ca 2+ into the presynaptic nerve terminal, synaptic vesicles disappeared and a large number of coated vesicles appeared. In addition, membrane invaginations developed involving not only the presynaptic membrane but also that of postsynaptic processes and glial cells. After injection of large quantities of Ca 2+ into the postsynaptic axon, electron-dense precipitates were seen also in the presynaptic terminal indicating retrograde transfer of material from post- to presynaptic axons.

scholarly journals Postsynaptic neuroligin-1 mediates presynaptic endocytosis during neuronal activity

2021 ◽  
Author(s):  
Jiaqi Keith Luo ◽  
Holly Melland ◽  
Jess Nithianantharajah ◽  
Sarah L Gordon
Keyword(s):  
Ampa Receptors ◽  
Neurotransmitter Release ◽  
Synaptic Vesicles ◽  
High Fidelity ◽  
Excitatory Synapses ◽  
Synaptic Efficacy ◽  
Molecular Architecture ◽  
Adhesion Protein ◽  
Presynaptic Nerve Terminal ◽  
Presynaptic Release

Fast, high-fidelity neurotransmission and synaptic efficacy requires tightly regulated coordination of pre- and postsynaptic compartments and alignment of presynaptic release sites with postsynaptic receptor nanodomains. Neuroligin-1 (Nlgn-1) is a postsynaptic cell-adhesion protein exclusively localised to excitatory synapses that is crucial for coordinating the transsynaptic alignment of presynaptic release sites with postsynaptic AMPA receptors as well as postsynaptic transmission and plasticity. However, little is understood about whether the postsynaptic machinery can mediate the molecular architecture and activity of the presynaptic nerve terminal, and thus it remains unclear whether there are presynaptic contributions to Nlgn1-dependent control of signalling and plasticity. Here, we employed a presynaptic reporter of neurotransmitter release and synaptic vesicle dynamics, synaptophysin-pHluorin (sypHy), to directly assess the presynaptic impact of loss of Nlgn1. We show that lack of Nlgn1 had no effect on the size of the readily releasable or entire recycling pool of synaptic vesicles, nor did it impact exocytosis. However, we observed significant changes in the retrieval of synaptic vesicles by compensatory endocytosis, specifically during activity. Our data extends growing evidence that synaptic adhesion molecules critical for forming transsynaptic scaffolds are also important for regulating activity-induced endocytosis at the presynapse.

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