Ultrastructure of synaptic vesicles and neurosecretory droplets in insect ganglia after controlled aldehyde fixation

Examination of variables of aldehyde fixation that may affect the shape of agranular synaptic vesicles has revealed that even brief storage of aldehyde-perfused nervous tissue pieces in cacodylate buffer, prior to hardening in osmium tetroxide, has an unusually severe flattening effect on agranular vesicles of a particular type. These are the vesicles of peripheral cholinergic axon endings, and of certain central synaptic bulbs. Types of synaptic bulbs can now be further defined on the basis of shape of agranular synaptic vesicles under controlled conditions of aldehyde fixation. Previously described "S" bulbs in the spinal cord contain uniformly spheroid vesicles, which are wholly resistant to flattening. Previously described "F" bulbs contain somewhat smaller agranular vesicles that are flattened after aldehyde fixation, even when this is followed by prompt hardening in osmium tetroxide solution. A third type, previously characterized as having irregularly round agranular vesicles after the above treatment, contains only severely flattened vesicles when the osmium tetroxide hardening is preceded by even a brief wash with sodium cacodylate buffer containing sucrose. Moreover, the "third" type is characteristic of all cholinergic peripheral axon endings examined, as well as the large axosomatic ("L") synaptic bulbs of the spinal cord.

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Cellular Contacts Within the Interhemal Membrane of the Rat Placenta at Term

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100050743 ◽

1974 ◽

Vol 32 ◽

pp. 146-147

Author(s):

William P. Jollie

Keyword(s):

Osmium Tetroxide ◽

Uranyl Acetate ◽

Capillary Endothelium ◽

En Bloc ◽

Aldehyde Fixation ◽

Chorioallantoic Placenta

By routine EM preparative techniques, the tissues which, collectively, separate maternal and fetal bloods in the fully formed chorioallantoic placenta of the rat have been shown to consist of three chorionic layers, or trophoblast, and a layer of allantoic capillary endothelium [Fig. 1]. Relationships between these layers are best demonstrated by special techniques, viz., cacodylate-buffered aldehyde fixation, collidine-buffered osmium tetroxide postfixation, and en bloc staining with uranyl acetate. By using this method on placentas at term, the cells of the outermost chorionic layer (Trophoblast 1) appear to be attached to each other by means of maculae adherentes which sometimes occur in clusters [Fig. 2].

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Complex Vesicles, Microtubules, and Cytoplasmic Filaments in the Endothelial Cells of Normal Dog Aorta

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100100603 ◽

1968 ◽

Vol 26 ◽

pp. 172-173

Author(s):

C. N. Sun ◽

J. J. Ghidoni

Keyword(s):

Electron Microscopy ◽

Endothelial Cells ◽

Cross Sections ◽

Functional Significance ◽

Tubular Structures ◽

Aldehyde Fixation ◽

Cytoplasmic Filaments

Endothelial cells in longitudinal and cross sections of aortas from 3 randomly selected “normal” mongrel dogs were studied by electron microscopy. Segments of aorta were distended with cold cacodylate buffered 5% glutaraldehyde for 10 minutes prior to being cut into small, well oriented tissue blocks. After an additional 1-1/2 hour period in glutaraldehyde, the tissue blocks were well rinsed in buffer and post-fixed in OsO4. After dehydration they were embedded in a mixture of Maraglas, D.E.R. 732, and DDSA.Aldehyde fixation preserves the filamentous and tubular structures (300 Å and less) for adequate demonstration and study. The functional significance of filaments and microtubules has been recently discussed by Buckley and Porter; the precise roles of these cytoplasmic components remains problematic. Endothelial cells in canine aortas contained an abundance of both types of structures.

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The Lateral Giant Fiber to Motor Giant Fiber Synapse in Crayfish

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100094103 ◽

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.

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

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100134508 ◽

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.

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

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100159539 ◽

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.

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