Sodium-dependent increase in quantal secretion induced by brevetoxin-3 in Ca 2+ -free medium is associated with depletion of synaptic vesicles and swelling of motor nerve terminals in situ

Neuroscience ◽  
1997 ◽  
Vol 78 (3) ◽  
pp. 883-893 ◽  
Author(s):  
F.A Meunier ◽  
C Colasante ◽  
J Molgo
Keyword(s):  
Synaptic Vesicles ◽  
Motor Nerve ◽  
Nerve Terminals ◽  
Free Medium ◽  
Motor Nerve Terminals ◽  
Sodium Dependent

scholarly journals Okadaic acid disrupts clusters of synaptic vesicles in frog motor nerve terminals

1994 ◽  
Vol 124 (5) ◽  
pp. 843-854 ◽  
Author(s):  
WJ Betz ◽  
AW Henkel
Keyword(s):  
Okadaic Acid ◽  
Synaptic Vesicles ◽  
Motor Nerve ◽  
Time Lapse ◽  
Nerve Terminals ◽  
Cell Nuclei ◽  
Motor Nerve Terminals ◽  
Electrophysiological Recordings ◽  
Translocation Mechanism ◽  
Active Zones

The fluorophore FM1-43 appears to stain membranes of recycled synaptic vesicles. We used FM1-43 to study mechanisms of synaptic vesicle clustering and mobilization in living frog motor nerve terminals. FM1-43 staining of these terminals produces a linear series of fluorescent spots, each spot marking the cluster of several hundred synaptic vesicles at an active zone. Most agents we tested did not affect staining, but the phosphatase inhibitor okadaic acid (OA) disrupted the fluorescent spots, causing dye to spread throughout the terminal. Consistent with this, electron microscopy showed that vesicle clusters were disrupted by OA treatment. However, dye did not spread passively to a uniform spatial distribution. Instead, time lapse movies showed clear evidence of active dye movements, as if synaptic vesicles were being swept along by an active translocation mechanism. Large dye accumulations sometimes occurred at sites of Schwann cell nuclei. These effects of OA were not significantly affected by pretreatment with colchicine or cytochalasin D. Electrophysiological recordings showed that OA treatment reduced the amount of acetylcholine released in response to nerve stimulation. The results suggest that an increased level of protein phosphorylation induced by OA treatment mobilizes synaptic vesicles and unmasks a powerful vesicle translocation mechanism, which may function normally to distribute synaptic vesicles between active zones.

scholarly journals Mobility of Synaptic Vesicles in Different Pools in Resting and Stimulated Frog Motor Nerve Terminals

Neuron ◽  
2006 ◽  
Vol 51 (3) ◽  
pp. 317-325 ◽  
Author(s):  
Michael A. Gaffield ◽  
Silvio O. Rizzoli ◽  
William J. Betz
Keyword(s):  
Synaptic Vesicles ◽  
Motor Nerve ◽  
Nerve Terminals ◽  
Motor Nerve Terminals

The role of extracellular calcium in exo- and endocytosis of synaptic vesicles at the frog motor nerve terminals

Neuroscience ◽  
2006 ◽  
Vol 143 (4) ◽  
pp. 905-910 ◽  
Author(s):  
A.L. Zefirov ◽  
M.M. Abdrakhmanov ◽  
M.A. Mukhamedyarov ◽  
P.N. Grigoryev
Keyword(s):  
Synaptic Vesicles ◽  
Motor Nerve ◽  
Extracellular Calcium ◽  
Nerve Terminals ◽  
Motor Nerve Terminals

scholarly journals Confocal Endomicroscopy of Neuromuscular Junctions Stained with Physiologically Inert Protein Fragments of Tetanus Toxin

Biomolecules ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 1499
Author(s):  
Cornelia Roesl ◽  
Elizabeth R. Evans ◽  
Kosala N. Dissanayake ◽  
Veronika Boczonadi ◽  
Ross A. Jones ◽  
...  
Keyword(s):  
Tetanus Toxin ◽  
Neuromuscular Junctions ◽  
Motor Nerve ◽  
Full Length ◽  
Nerve Terminals ◽  
Motor Nerve Terminals ◽  
Mouse Muscle ◽  
Confocal Endomicroscopy ◽  
Derivatives Of

Live imaging of neuromuscular junctions (NMJs) in situ has been constrained by the suitability of ligands for inert vital staining of motor nerve terminals. Here, we constructed several truncated derivatives of the tetanus toxin C-fragment (TetC) fused with Emerald Fluorescent Protein (emGFP). Four constructs, namely full length emGFP-TetC (emGFP-865:TetC) or truncations comprising amino acids 1066–1315 (emGFP-1066:TetC), 1093–1315 (emGFP-1093:TetC) and 1109–1315 (emGFP-1109:TetC), produced selective, high-contrast staining of motor nerve terminals in rodent or human muscle explants. Isometric tension and intracellular recordings of endplate potentials from mouse muscles indicated that neither full-length nor truncated emGFP-TetC constructs significantly impaired NMJ function or transmission. Motor nerve terminals stained with emGFP-TetC constructs were readily visualised in situ or in isolated preparations using fibre-optic confocal endomicroscopy (CEM). emGFP-TetC derivatives and CEM also visualised regenerated NMJs. Dual-waveband CEM imaging of preparations co-stained with fluorescent emGFP-TetC constructs and Alexa647-α-bungarotoxin resolved innervated from denervated NMJs in axotomized WldS mouse muscle and degenerating NMJs in transgenic SOD1G93A mouse muscle. Our findings highlight the region of the TetC fragment required for selective binding and visualisation of motor nerve terminals and show that fluorescent derivatives of TetC are suitable for in situ morphological and physiological characterisation of healthy, injured and diseased NMJs.

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