Changes in the distribution and size of synaptic vesicles in neuromuscular junctions of Locusta migratoria after stimulation and rest

1979 ◽  
Vol 203 (3) ◽  
Author(s):  
R.P. Botham ◽  
D.J. Beadle ◽  
R.J. Hart ◽  
C. Potter ◽  
R.G. Wilson
Author(s):  
M. Reinecke ◽  
Ch. Walther

The zinc iodide-osmium tetroxide reaction (ZIO) was first used in neurobiological research by Maillet (Bull. Ass. Anat. 53, 233; 1968). Subsequently several authors have shown that, under appropriate conditions, ZIO stains mainly the interior of synaptic vesicles. The substrate of this reaction is under discussion, since ZIO can also react with other subcellular structures in a variety of tissues, e. g. mitochondria, endoplasmic reticulum, dictyosomes and lysosomes. Additionally, in vitro substances as different as some aminoacids, catecholamines, aldehydes and phospholipids (Pellegrino de Iraldi, Experientia 33, 1; 1977) can yield black precipitations with ZIO.Our studies were done with the motor nerve terminals at the femoral retractor unguis muscle of the locust (Locusta migratoria). These terminals are chiefly the endings of excitatory motoraxons and are characterized by the presence of electron lucent vesicles and by an accumulation of mitochondria.


1979 ◽  
Vol 203 (3) ◽  
Author(s):  
R.P. Botham ◽  
D.J. Beadle ◽  
R.J. Hart ◽  
C. Potter ◽  
R.G. Wilson

1971 ◽  
Vol 178 (1053) ◽  
pp. 407-415 ◽  

When frog muscles are exposed for several hours to a solution of isotonic calcium chloride, the secretory response of the motor nerve terminals to imposed depolarization ultimately fails and the rate of spontaneous release of acetylcholine also declines towards zero. The failure of depolarization-evoked transmitter release is irreversible while spontaneous release reappears, though in highly abnormal fashion, when the muscle is returned to a normal ionic medium. Examination of motor end-plates, during various stages of calcium treatment, shows that there is gradual intra-axonal agglutination of synaptic vesicles which is only very incompletely reversible. This effect is presumably the consequence of gradual entry and intracellular accumulation of calcium ions. Analogous treatment with isotonic magnesium, while resulting in immediate loss of evoked transmitter release, does not lead to progressive agglutination of synaptic vesicles, nor to irreversible impairment of the secretory response of the nerve terminal. The possible relations between structural and functional changes during calcium and magnesium treatment are discussed.


Neuroreport ◽  
2011 ◽  
Vol 22 (4) ◽  
pp. 185-189 ◽  
Author(s):  
Qingbo Wang ◽  
Sadie L. Hebert ◽  
Mark M. Rich ◽  
Susan D. Kraner

1969 ◽  
Vol 17 (3) ◽  
pp. 161-170 ◽  
Author(s):  
SUMNER I. ZACKS ◽  
ATUSHI SAITO

Following intramuscular injection of horseradish peroxidase into mouse skeletal muscle adjacent to areas of innervation, rapid uptake of the label was observed by coated but not synaptic vesicles. The tracer was also found in Schwann cells, external mesaxons and within peripheral myelin lamellae, but never in axoplasm of intramuscular nerves proximal to the injection site. The data suggest that the tracer is taken up by the coated vesicles and may be rapidly discharged into the synaptic clefts from which it is cleared by a combination of phagocytic activity and absorption via pinocytotic vesicles and intercellular clefts of adjacent capillaries or, more probably, enzyme activity is lost within the coated vesicles. The significance of these observations as related to neuromuscular function is discussed.


1979 ◽  
Vol 203 (3) ◽  
Author(s):  
R.P. Botham ◽  
D.J. Beadle ◽  
R.J. Hart ◽  
C. Potter ◽  
R.G. Wilson

2014 ◽  
Vol 205 (1) ◽  
pp. 21-31 ◽  
Author(s):  
Dong Wang ◽  
Daniel Epstein ◽  
Ossama Khalaf ◽  
Sankaranarayanan Srinivasan ◽  
W. Ryan Williamson ◽  
...  

Most chemical neurotransmission occurs through Ca2+-dependent evoked or spontaneous vesicle exocytosis. In both cases, Ca2+ sensing is thought to occur shortly before exocytosis. In this paper, we provide evidence that the Ca2+ dependence of spontaneous vesicle release may partly result from an earlier requirement of Ca2+ for the assembly of soluble N-ethylmaleimide–sensitive fusion attachment protein receptor (SNARE) complexes. We show that the neuronal vacuolar-type H+-adenosine triphosphatase V0 subunit a1 (V100) can regulate the formation of SNARE complexes in a Ca2+–Calmodulin (CaM)-dependent manner. Ca2+–CaM regulation of V100 is not required for vesicle acidification. Specific disruption of the Ca2+-dependent regulation of V100 by CaM led to a >90% loss of spontaneous release but only had a mild effect on evoked release at Drosophila melanogaster embryo neuromuscular junctions. Our data suggest that Ca2+–CaM regulation of V100 may control SNARE complex assembly for a subset of synaptic vesicles that sustain spontaneous release.


eLife ◽  
2013 ◽  
Vol 2 ◽  
Author(s):  
Shigeki Watanabe ◽  
Qiang Liu ◽  
M Wayne Davis ◽  
Gunther Hollopeter ◽  
Nikita Thomas ◽  
...  

Synaptic vesicles can be released at extremely high rates, which places an extraordinary demand on the recycling machinery. Previous ultrastructural studies of vesicle recycling were conducted in dissected preparations using an intense stimulation to maximize the probability of release. Here, a single light stimulus was applied to motor neurons in intact Caenorhabditis elegans nematodes expressing channelrhodopsin, and the animals rapidly frozen. We found that docked vesicles fuse along a broad active zone in response to a single stimulus, and are replenished with a time constant of about 2 s. Endocytosis occurs within 50 ms adjacent to the dense projection and after 1 s adjacent to adherens junctions. These studies suggest that synaptic vesicle endocytosis may occur on a millisecond time scale following a single physiological stimulus in the intact nervous system and is unlikely to conform to current models of endocytosis.


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