ISSN:1059-910X    

DOI:10.1002/jemt.1070230402

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1992

数据来源: WILEY

摘要:

AbstractThis paper describes the early stages of impregnation by the Golgi rapid method in sections and blocks of brain tissue. Aldehyde‐fixed and potassium dichromate–treated sections of cerebral cortex were placed on glass slides and coverslipped. The dichromate solution was then replaced by a silver nitrate solution, and events taking place in the section were monitored and time‐lapse recorded until the impregnation was interrupted and the sections subsequently prepared for electron microscopy. The tissue blocks, fixed and chromated in the same way, were placed into a silver nitrate solution for 30 min to 24 h and the progress of impregnation compared with the results obtained in the sections on the glass slides.Two basic modes of impregnation were observed, apparently in direct relation to the process of crystallization of silver chromate: crystals of silver chromate growing directly from the surface of the tissue into the nerve cell via its transected plasma membranes, and microcrystalline precipitate of silver chromate spreading into the nerve cell from nucleation centres dispersed in the tissue. The precipitate grows inside the cell as in a preformed channel until the cell has been filled. If the nucleation begins extracellularly, the precipitate extends into the narrow intercellular gaps. Electron microscopy showed that the crystalline precipitate consisted of multilamellar formations containing dense coalesced granules that did not cross plasma or endocellular membrane boundaries. © 1992 Wiley‐L

ISSN:1059-910X    

DOI:10.1002/jemt.1070230403

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1992

数据来源: WILEY

摘要:

AbstractDirect electron microscopy of nervous tissue stained with the Golgi impregnation method is unsatisfactory because the cytoplasm of the cell bodies and processes of the impregnated neurons are completely filled with a compact precipitate of electron dense silver chromate. This precipitate entirely obscures the cytological details of the impregnated neurons. Because of its solidity and instability in aqueous solutions, the silver chromate is also a source of inconvenience during the preparation of the ultrathin sections.This review summarizes methods that have been developed with the aim of replacing the Golgi precipitate in CNS neurons with a more convenient electron dense material—for example, heavy metal salts or metallic particles. Conversion of the precipitate into a stable electron dense marker is done before the material is embedded for electron microscopy. The methods include lead, gold, and bromide substitution, treatment with ammonia, direct chemical reduction into metallic silver, and photoreduction of the silver chromate into silver through irradiation with ultraviolet light. © 1992 Wiley‐Liss,

ISSN:1059-910X    

DOI:10.1002/jemt.1070230404

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1992

数据来源: WILEY

摘要:

AbstractThe Golgi‐electron microscope technique has opened new avenues to explore the synaptic organization of the brain. In this article, we shall discuss basic methodological principles necessary to analyze axonal arborizations with this combined technique. To illustrate the applications of the method, we shall review the forms and distribution of the synapses in which the axonal arborizations of local cortical interneurons engage. © 1992 Wiley‐Liss,

ISSN:1059-910X    

DOI:10.1002/jemt.1070230405

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1992

数据来源: WILEY

摘要:

AbstractIn this study the Golgi/electron microscopy (EM) technique has been used for an analysis of the fine structure, specific synaptic connections, and differentiation of neurons in the hippocampus and fascia dentata of rodents. In a first series of experiments the specific synaptic contacts formed between cholinergic terminals and identified hippocampal neurons were studied. By means of a variant of the section Golgi impregnation procedure, Vibratome sections immunostained for choline acetyltransferase, the acetylcholine‐synthesizing enzyme, were Golgi‐impregnated in order to identify the target neurons of cholinergic terminals in the hippocampus. It could be shown with this combined approach that cholinergic septohippocampal fibers form a variety of synapses with different target structures of the Golgi‐impregnated and gold‐toned hippocampal neurons. In this report cholinergic synapses on the heads of small spines, the necks of large complex spines, dendritic shafts, and cell bodies of identified dentate granule cells are described. The variety of cholinergic synapses suggests that cholinergic transmission in the fascia dentata is a complex event.Next, the Golgi/EM technique was applied to Vibratome sections that contained retrogradely labeled neurons in the hilar region of the fascia dentata following horseradish peroxidase (HRP) injection into the contralateral hippocampus. With this combined approach some of the hilar cells projecting to the contralateral side were identified as mossy cells by the presence of retrogradely transported HRP in thin sections through these Golgi‐impregnated and gold‐toned neurons. Our findings suggest that the mossy cells are part of the commissural/associational system terminating in the inner molecular layer of the fascia dentata. They are mainly driven by hilar collaterals of granule cell axons that form giant synapses on their dendrites.Finally, the Golgi/EM procedure was used to study the differentiation and developmental plasticity of hippocampal and dentate neurons in transplants and slice cultures of hippocampus. Under both experimental conditions, the differentiating neurons are deprived of their normal laminated afferent innervation but develop their major cell‐specific characteristics including a large number of postsynaptic structures (spines). As revealed in thin sections of gold‐toned identified cells, all these spines formed synapses with presynaptic boutons suggesting sprouting of the transplanted and cultured neurons, respectively.Altogether, the present report demonstrates the usefulness of the Golgi/EM technique, particularly of the section impregnation procedure, for a variety of studies requiring the identification of individual neurons at the ultrastructural level. © 1992

ISSN:1059-910X    

DOI:10.1002/jemt.1070230406

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1992

数据来源: WILEY

摘要:

AbstractThe combined light and electron microscopic analysis of Golgi‐impregnated neural tissue is a potent tool for determining the connectivity of neural networks within the brain. In the experimental paradigms commonly applied in these studies, the Golgi‐impregnated neurons are typically examined as the postsynaptic neuronal components. The structural characteristics and the pattern of distribution of their synaptic connections with other groups of identified neurons are analyzed. Due to the high power of resolution of the Golgi‐electron microscopic technique, the ultrastructural analysis of Golgi‐impregnated neurons can be expanded to elucidate activity‐dependent structural alterations in their cytoarchitecture. These structural alterations can then be correlated under different physiological conditions with changes in the functional efficacy of the subcellular neuronal components. © 1992 Wiley

ISSN:1059-910X    

DOI:10.1002/jemt.1070230407

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1992

数据来源: WILEY

摘要:

AbstractWith the classical Golgi techniques, numerous types of neurons can be distinguished in the cerebral cortex, each with a specific dendritic geometry and pattern of axonal ramifications. In the present review we describe two techniques which allow quantification of synapses on identified neurons: (1) Golgi‐rapid impregnation‐gold toning‐electron microscopy, and (2) Golgi‐Kopsch impregnation‐gold toning‐electron microscopy in combination with staining of the tissue with ethanolic phosphotungstic acid (E‐PTA). Both techniques were applied on neurons in the visual cortex of young and adult rabbits. By means of rotating and tilting specimens in the electron microscope, the nondistinctive ultrastructure of obliquely sectioned synapses can be circumvented, leading to precise estimates of asymmetrical vs. symmetrical synapses without complete reconstruction of the neuron. © 1992 W

ISSN:1059-910X    

DOI:10.1002/jemt.1070230408

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1992

数据来源: WILEY

ISSN:1059-910X    

DOI:10.1002/jemt.1070230409

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1992

数据来源: WILEY

ISSN:1059-910X    

DOI:10.1002/jemt.1070230401

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1992

数据来源: WILEY