Electron-dense Particle in Cholinergic Synaptic Vesicles

Nature ◽  
1973 ◽  
Vol 244 (5410) ◽  
pp. 32-34 ◽  
Author(s):  
T. P. BOHAN ◽  
A. F. BOYNE ◽  
P. S. GUTH ◽  
Y. NARAYANAN ◽  
T. H. WILLIAMS
Keyword(s):  
Synaptic Vesicles ◽  
Dense Particle ◽  
Electron Dense Particle

scholarly journals EFFECTS OF CALCIUM-CONTAINING FIXATION SOLUTIONS ON CHOLINERGIC SYNAPTIC VESICLES

1974 ◽  
Vol 63 (3) ◽  
pp. 780-795 ◽  
Author(s):  
Alan F. Boyne ◽  
Timothy P. Bohan ◽  
Terence H. Williams
Keyword(s):  
Binding Sites ◽  
Synaptic Vesicles ◽  
Chelating Agents ◽  
Electric Organ ◽  
Morphological Evidence ◽  
Nerve Terminals ◽  
Vesicle Membrane ◽  
Dense Particle ◽  
Thin Sections ◽  
Electron Dense Particle

Calcium (Ca)-containing fixation solutions applied to slices of electric organ of the electric ray, Narcine brasiliensis, have been shown to have three distinct ultrastructural effects on cholinergic synaptic vesicles of the nerve terminals. (a) An electron-dense particle (EDS) is observed within the vesicle; the particle is seen in unosmicated, unstained tissues and can be removed from thin sections by Ca-chelating agents. It is concluded that the EDS represents Ca bound by the vesicle. It is suggested that the bound ATP of the vesicle provides anionic Ca binding sites. (b) The vesicle membrane tends to ‘crinkle’ or collapse depending on the concentration of the other components of the fixative solution. The ‘crinkling’ or collapse are largely reversed by a wash step in the absence of Ca. (c) The presence of Ca results in the appearance of a population of vesicles which form characteristic fusions or ‘tight’ junctions with the terminal membrane. This appears to be morphological evidence for the proposal, which has been frequently put forward, that Ca facilitates such a fusion before discharge of vesicle-bound transmitter. With the discovery that the use of Ca-containing fixatives leads to the demonstration of a subpopulation of synaptic vesicles fused to the terminal membrane, we are led to propose that this is the ultrastructural location of the newly synthesized acetylcholine which has been shown by others to be preferentially released by stimulation.

scholarly journals Protein W, a spore-specific protein inMyxococcus xanthus, formation of a large electron-dense particle in a spore

1998 ◽  
Vol 30 (1) ◽  
pp. 57-66 ◽  
Author(s):  
Mieko Otani ◽  
Satoshi Kozuka ◽  
Chunying Xu ◽  
Chisae Umezawa ◽  
Keijo Sano ◽  
...  
Keyword(s):  
Specific Protein ◽  
Dense Particle ◽  
Electron Dense Particle

The Lateral Giant Fiber to Motor Giant Fiber Synapse in Crayfish

1972 ◽  
Vol 30 ◽  
pp. 170-171
Author(s):  
Charles A. Stirling
Keyword(s):  
Synaptic Vesicles ◽  
Procambarus Clarkii ◽  
Synaptic Contact ◽  
Giant Fiber ◽  
Synaptic Junctions

The lateral giant (LG) to motor giant (MoG) synapses in crayfish (Procambarus clarkii) abdominal ganglia are the classic electrotonic synapses. They have previously been described as having synaptic vesicles and as having them on both the pre- and postsynaptic sides of symmetrical synaptic junctions. This positioning of vesicles would make these very atypical synapses, but in the present work on the crayfish Astacus pallipes the motor giant has never been found to contain any type of vesicle at its synapses with the lateral giant fiber.The lateral to motor giant fiber synapses all occur on short branches off the main giant fibers. Closely associated with these giant fiber synapses are two small presynaptic nerves which make synaptic contact with both of the giant fibers and with their small branches.

Opening images of synaptic vesicles and calcium localization by means of microwave fixation method

1990 ◽  
Vol 48 (2) ◽  
pp. 182-183
Author(s):  
Vinci Mizuhira ◽  
Hiroshi Hasegawa
Keyword(s):  
Synaptic Vesicles ◽  
Room Temperature ◽  
Osmium Tetroxide ◽  
Sampling Procedure ◽  
Fixation Method ◽  
Potassium Oxalate ◽  
X Ray ◽  
Cacodylate Buffer ◽  
Ultrathin Sections ◽  
Microwave Fixation

Microwave irradiation (MWI) was applied to 0.3 to 1 cm3 blocks of rat central nervous system at 2.45 GHz/500W for about 20 sec in a fixative, at room temperature. Fixative composed of 2% paraformaldehyde, 0.5% glutaraldehyde in 0.1 M cacodylate buffer at pH 7.4, also contained 2 mM of CaCl2 , 1 mM of MgCl2, and 0.1% of tannic acid for conventional observation; and fuether 30-90 mM of potassium oxalate containing fixative was applied for the detection of calcium ion localization in cells. Tissue blocks were left in the same fixative for 30 to 180 min after MWI at room temperature, then proceeded to the sampling procedure, after postfixed with osmium tetroxide, embedded in Epon. Ultrathin sections were double stained with an useal manner. Oxalate treated sections were devided in two, stained and unstained one. The later oxalate treated unstained sections were analyzed with electron probe X-ray microanalyzer, the EDAX-PU-9800, at 40 KV accelerating voltage for 100 to 200 sec with point or selected area analyzing methods.

Evaluation of hippocampus in rhesus monkeys after chronic (1-year) inhalation exposure to marijuana: I. Electron microscopy

1990 ◽  
Vol 48 (3) ◽  
pp. 398-399
Author(s):  
A.M. Andrews ◽  
S.W. Wilson ◽  
A.C. Scallet ◽  
S.F. Ali ◽  
J. Bailey ◽  
...  
Keyword(s):  
Synaptic Vesicles ◽  
Rhesus Monkeys ◽  
Low Dose ◽  
Inhalation Exposure ◽  
Synaptic Cleft ◽  
High Dose ◽  
Withdrawal Time ◽  
Treatment Groups ◽  
Ultrastructural Evidence ◽  
Male Rhesus

Exposure of rhesus monkeys (Macaca mulatta) to marijuana via inhalation or to intravenous delta-9-tetrahydrocannabinol (THC), reportedly caused ultrastructural evidence of increased synaptic width. Chronic marijuana smoke in a single rhesus monkey examined after a six month withdrawal time caused ultrastructure changes in the septal, hippocampal and amygdala regions; the synaptic cleft was widened, electron opaque material was found in the cleft and in the pre- and postsynaptic regions, with some clumping of the synaptic vesicles. The objective of our study was to assess neuropathological alterations produced by chronic inhalation of marijuana smoke.Nineteen male rhesus monkeys, 3-5 years of age and weighing 3-8 kg, were divided into four treatment groups: a) sham control, b) placebo smoke (7 days/ week) c) low dose marijuana (2 times/week with 5 days/week sham) and d) high dose marijuana (7 times/week). A smoke exposure consisted of smoke from one cigarette (2.6% THC) burned down to 10 mm butt length. Smoke was administered via smoke generator (ADL II, Arthur D. Little, Inc. Cambridge, MA) and nose-mouth only masks (local production) equipped with one-way valves.

NUMERICAL SIMULATION OF THE COMPACTION EFFECT DURING SHOCK WAVE € PARTICLE LAYER NUMERICAL SIMULATION OF THE COMPACTION EFFECT DURING SHOCK WAVE-PARTICLE LAYER INTERACTION

2020 ◽  
Author(s):  
YA. E. POROSHYNA ◽  
◽  
P. S. UTKIN ◽  
Keyword(s):  
Numerical Simulation ◽  
Shock Wave ◽  
Dust Explosion ◽  
Dense Particle ◽  
Layer Interaction ◽  
Particle Layer ◽  
Complex Process ◽  
Impermeable Wall

The problem of shock wave - dense particle layer interaction is a fundamental basis for the study of a more complex process of dust explosion or dust-layered detonation. The work presents results of numerical simulation of the experiment on interaction of an SW with particles layer deposited on the impermeable wall.

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