• Applied Microscopy
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• v.35 no.1
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• pp.31-39
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• 2005

Synapses are contact points where one neuron communicates with another. The morphological change of synapses under various physiological or pathological conditions has long been hypothesized to modify their functional properties. 3-dimensional (3-D) reconstruction of synapses with serial ultrathin sections has contributed to the understanding of ultrastructural dimensions and compositions of synapses. The 3-D reconstruction procedures, however, require a great amount of expertise as well as include prohibitively timeconsuming processes. Here, we introduce efficient 3-D reconstruction technique using high-voltage electron microscopy (HVEM). Primarily, we established an optimal section thickness and staining condition to observe synaptic structures in detail under HVEM. The result showed that synaptic profiles were preserved at the section thickness of 250 nm without the overlapping of synaptic ultrastructures. An increase in the reaction time of en bloc staining was most efficient to enhance contrast than the extension of postembedding staining or the addition of uranyl acetate during dehydration. Then, 3-D reconstruction of parallel fiber-Purkinje cell synapses in the rat cerebellum was carried out with serial HVEM images and reconstruction software. The images were aligned and the contours of synapses were outlined on each section. 3-D synapses were finally extracted from the section files by grouping all the synaptic contours. The reconstructed synapse model clearly demonstrated the configuration of pre and postsynaptic components. These results suggest that 3-D reconstruction of synapses using HVEM is much efficient and suitable for massive quantitative studies on synaptic connectivity than conventional TEM approach using numerous ultrathin sections.

• Applied Microscopy
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• v.25 no.4
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• pp.83-103
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• 1995

This experiment was carried out to investigate the effects of telluric acid on the histological and fine structural changes in the rat liver. Fischer 344 rats($150{\sim}200gm$) were used in this study as control and experimental groups. Telluric acid(5 mg/100 gm of body weight) suspensed in olive oil was given intraperitoneally to the animals of the experimental group and only olive oil to those of the control group. At the intervals of 3, 6 and 12 hours, 1, 2, 3, 5, 10, 20, 30 and 60 days after administration, the animals were sacrificed, and livers were obtained from the rats. For light microscopic examination of the liver, sections($5{\mu}m$) were stained with hematoxylineosin(H-E). For electron microscopic examination of the liver, sections were stained with uranyl acetate and lead citrate, finally examined with Zeiss EM 109 electron microscopes. The results obtained were as follows. 1. In the control group, round nucleus. well developed mitochondria, Golgi apparatus, rough endoplasmic reticulum(RER) and numerous glycogen particles were observed in the cytoplasm of the hepatocyte. In the cytoplasmic membranes of the hepatocyte, sinusoidal surface had numerous microvilli and cellular surface is combinated adjacent hepatocyte with desmosomes. The RER cisterns were dilated and zymogen granules were fewer than those of the dark cells. Kupffer cells with irregular nuclear membrane were observed. Fat storing cell and collagenous fiber bundle were observed in the Disse space. 2. Kupffer cell, inflammatory cells in the connective tissue of hepatic triad and lysosome were increased in the 3, 6, and 12 hour experimental group comparing with that of the control group. 3. In the 1 day experimental group, infiltration of inflammatory cells in interlobular connective tissue, dilatation of sinusoidal capillary and increasing of Kupffer cell were observed. Atropic change of hepatocyte and aggregation of glycogen particles in the cytoplasm of hepatocyte were observed. In this group, desmosome near bile canaliculi and collagenous fiber bundle in the Disse space were increased comparing with that of the 12 hours experimental group. In the 2 days experimental group, desmosome, lysosome, peroxisome and collagenous fiber bundle were increased comparing with that of the 1 day experimental group. Furthermore, lamellated bodies were also seen in the cytoplasm of the hepatocyte. 4. In 3 and 5 days experimental groups, transformations of hepatic cell cord and degeneration of the hepatocyte were markedly inclosed comparing with the all experimental groups. And damaged RER and mitochondria. collagenous fiber bundle were also inclosed comparing with that of the 2 days experimental group. Autophagosome and fat storing cells with large lipid droplets were also observed comparing with that of the 2 days experimental group. Tight junction and desmosome between the hepatocytes were separated. These degenerating changes were severe through the all experimental groups. 5. In the 10 and 20 days experimental groups, arrangement of hepatic cell cords and cell organelles of hepatocytes were similar to those of the control group. However, aggregation of glycogen particles, dilatation of sinusoidal capillary and infiltration of inflammatory cells remained. 6. In the 30 days experimental group, the tissue findings were similar to those of the control grout. But lamellated bodies in some hepatocytes and lysosome were remained in the cytoplasms of the Kupffer cells. In the 60 days experimental group, these all changes were recovered as the control group. In conclusion, telluric acid would directly induce the degenerative and necrotic changes on the hepatic tissue. However, these changes were perfectly recoverd in the 60 days experimental group as the control group.