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  • 1975-1979  (7)
  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Anatomy and embryology 152 (1977), S. 15-27 
    ISSN: 1432-0568
    Keywords: Fish cerebellum ; Acetylcholinesterase ; Ultrastructural cytochemistry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The histochemical localization of acetylcholinesterase (AChE) was studied by electron microscopy in the cerebellar cortex of the goldfish and the catfish. The patterns of enzyme distribution show noticeable differences in the two teleost species at the level of the corresponding cerebellar structures. Among the most distinctive features in the prevailing intracellular localization of enzyme activity in the goldfish and the prevailing extracellular localization in the catfish in the molecular layer and, to a lesser extent, the granular layer. Only quantitative differences in the ability to synthesize AChE can be recorded among the different cerebellar neurons in the two species, since all these neurons exhibit different amounts of enzyme activity linked to their cytoplasmic structures. Comparing the results obtained with those of previous histochemical, experimental and developmental researches, the hypothesis seems well founded that the embryonic pool of cerebellar neurons is made up to AChE-synthesizing neuroblasts which, during development, lose or maintain to a different degree the mechanisms for AChE synthesis. In addition the light and electron microscope histochemistry reveals at different levels of resolution that the final pattern of AChE distribution in the cerebellar cortex is the sum of different degrees of AChE synthesis by cerebellar neurons and different degrees of enzyme release in extracellular spaces.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Anatomy and embryology 152 (1977), S. 29-41 
    ISSN: 1432-0568
    Keywords: Cerebellum ; Acetylcholinesterase ; Ultrastructural cytochemistry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The ultrastructural localization of acetylcholinesterase (AChE) was studied in the cerebellar cortex of the quail by means of histochemical methods. The greater amount of AChE was detected at level of the molecular layer in the intercellular spaces between parallel fibers and between parallel fibers and dendritic terminals. Many neurons showed intracellular localization of enzyme activity: the AChE positive neurons were all Golgi cells, most stellate and basket cells and different aliquots of Purkinje and granule cells. The enzymatic activity was usually localized in the cisternae of endoplasmic reticulum, in the nuclear envelope (but this last localization was not present in Purkinje cells) and sometimes in the Golgi apparatus; reaction granules were usually scarce in the different dendritic branches ramifying in the molecular layer. On the basis of the ultrastructural pattern of AChE distribution, some considerations are developed on the methodological aspects concerning the reliability of histochemical methods, the differences recorded at light and electron microscope level, the problems related to extracellular localization of enzyme, the difficulty of establishing a precise correlation between AChE localization in a cerebellar neuron and its possible cholinergic and/or cholonoceptive nature.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Histochemistry and cell biology 53 (1977), S. 117-133 
    ISSN: 1432-119X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Under histochemical conditions (fresh frozen sections from liver, kidney and cerebellum of the rat) it was shown that the oxidation of L-glutamic acid was carried out by the NAD-dependent L-glutamate dehydrogenase (E.C. 1.4.1.2) and/or the NAD- or NADP-dependent L-glutamate dehydrogenase (E.C. 1.4.1.3) as well as by an enzyme system which is not dependent on externally added NAD, NADP, FAD, FMN or CoQ10 for activity. This non-pyridine dependent activity was related to the L-glutamate dehydrogenases proper, owing to the following: a) the localization of activity noticed corresponds to that obtained with the NAD- or NADP-containing media, b) the incubation time needed for initial formation of red and blue formazans is similar to that with coenzyme-containing media, c) pre-extraction experiments reveal similarity in enzyme diffusion rates, d) the named activity is influenced by the same agents and to the same extent as the activity obtained by the inclusion of NAD or NADP (e.g. dissociation of the dehydrogenase molecule into subunits due to urea, inhibition of activity due to N-ethyl maleimide and 1.10-phenanthroline, activation due to the allosteric effect of ADP and to high substrate concentration, allosteric inhibition caused by GTP and inhibition caused by α-ketoglutaric acid, no inhibitory effect of KCN), and e) the named activity was not affected by added PMS (excluding activity due to L-aminoacid oxidase). In the in situ localization of enzyme activity it was found that L-glutamate dehydrogenases E.C. 1.4.1.2 and E.C. 1.4.1.3 co-exist in the cells of kidney and cerebellum, while the L-glutamate dehydrogenase E.C. 1.4.1.3 only was present in liver cells. Finally, it was stated that incubation time should be kept as short as possible in order to avoid “Nothing dehydrogenase” reaction as well as inhibition due to accumulation of α-ketoglutaric acid. Only “gel” incubation media should be applied.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Histochemistry and cell biology 56 (1978), S. 117-132 
    ISSN: 1432-119X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary In a detailed study focused on the methodological problems in dehydrogenase histochemistry [e.g., fixation, diffusion of enzymes and of reduced inermediates, conversion of NADPH and NADP to NADH and NAD, respectively, penetration of tetrazolium salt and formazan substantivity, ‘nothing dehydrogenase’ reaction, use of exogenous CoQ10 and of flavoprotein substitute (PMS)], the distribution and activity of succinate dehydrogenase, NAD(P)H-tetrazolium reductase, glucose-6-phosphate dehydrogenase, lactate dehydrogenase (H and M types), and of l-glutamate dehydrogenase (E.C. 1.4.1.2 and E.C. 1.4.1.3) have been investigated in the rat cerebellum. It was evident from the study that reliable results could only be obtained if all the aforementioned factors had been considered. The image of actual concentration of SDH in the neuropil of the molecular layer could only be recorded by adding CoQ10, while other structures exhibited greater balance between SDH and endogenous mitochondrial CoQ. Contrary to previous studies, a reversed localization of the activity of G-6-PDH and LDH was noticed. The elements of molecular and Purkinje layers were rich in G-6-PDH, while the granular layer was nearly depleted. The actual level of LDH could only be recorded if NADH-tetrazolium reductase was bypassed with PMS. The H and M types of LDH coexisted in the three cortical layers, the H type being prevalent and the M type attaining its highest level in synaptic glomeruli followed by the structures of the molecular layer and the Purkinje cells. High activity of GDH was noticed in Bergmann glia followed by synaptic glomeruli, while most other structures showed weak to moderate activity. The two GDH types coexisted in all structures showing activity, except for Bergmann cells, which only showed presence of the E.C. 1.4.1.3 type. Furthermore, Bergmann glia was exceptional by showing no activity of SDH and LDH, but strong activity of G-6-PDH and NADPH-tetrazolium reductase. The granular cells were exceptional by showing weak or no activity of all enzymes in question.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Histochemistry and cell biology 51 (1977), S. 195-200 
    ISSN: 1432-119X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary In the cerebellum of four species belonging to the three main reptilian orders the histochemical localization of cholinesterases has been studied. The use of different substrate-inhibitor combinations permits to record the distribution patterns of acetylcholinesterase and pseudocholinesterase, mainly revealed as butyrylcholinesterase activity. From the neurological point of view it is interesting to note that acetylcholinesterase activity shows three different distribution patterns in reptilian cerebellum, thus confirming the characteristic variability previously noticed in the cerebellar cortex of other vertebrates.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Histochemistry and cell biology 45 (1975), S. 279-288 
    ISSN: 1432-119X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary A histochemical study has been carried out on the localization of acetylcholinesterase (AChE) in the cerebellum and optic tectum of four species of freshwater teleosts. AChE distribution in the cerebellar cortex of teleosts shows differences among the species examined and, in the trout, also differences between different cerebellar areas. This uneven kind of enzyme distribution corresponds to a similar variety of AChE patterns noticed in other vertebrates, especially mammals. AChE distribution in the optic tectum shows a prevalent pattern characterized by precise laminar distribution of enzymatic activity which is alternatively strong, weak or absent in the different tectal layers. The results suggest that most of sensitive imput and many systems of stimuli propagation may be mediated by cholinergic mechanisms in the optic tectum of teleosts.
    Type of Medium: Electronic Resource
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  • 7
    ISSN: 1573-7381
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary A histochemical study of the ultrastructural localization of ATPases in cultures of chick embryo spinal cord has been carried out. The localization of Ca2+ and Mg2+ activated membrane ATPases appears similar: both enzyme activities are localized on the outer surfaces of plasma membranes of all kinds of cell present in the cultures, with the exception of the membranes in direct contact with the culture medium. The results are discussed in relation to data concerning the localization and function of ATPasesin vivo and in relation to the possible establishment of mechanisms of nutrient uptake and transfer in cultures of nervous tissue.
    Type of Medium: Electronic Resource
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