Zinc content in hippocampus and whole brain of normal rats (original) (raw)
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Cytoarchitectonic distribution of zinc in the hippocampus of man and the rat
Brain Research, 1983
Zinc was measured in whole hippocampus and in hippocampal sub-regions by stable-isotope dilution mass spectrometry. In both man and the rat, the most zinc (102-145 ppm, dry weight) was found in the hilar region, the least (27-35) in the fimbria. The amount of zinc directly associated with mossy-fiber axons was estimated to be approximately 8% of the total zinc in the hippocampus, and the concentration of mossy-fiber zinc was estimated at 220-300 #M. Methodological and theoretical implications of the quantitative findings were discussed. 0006-8993/83/$03.00
Heavy metal content in subdivisions of the rat hippocampus (zinc, lead and copper)
Brain Research, 1976
In recent years the Timm sulphide silver method lz for the histochemical demonstration of heavy metals has served as the starting point for a series of investigations into the nature and function of metals in the hippocampal region. It was suggested by studies with this method, and confirmed by flameless atomic absorption spectrophotometry, that the hippocampus and amygdala accumulate zinc and lead far in excess of the average contents of the whole brain 1,3,5,6. The giant boutons of the hippocampal mossy fibre system are especially strongly stained by the Timm method 4, s.9, and this has been postulated to be due to their content of zinc. It has further been shown that application of chelating drugs, which abolish Timm stainability, has pronounced behavioural effects 1,2,7,n. The present study was undertaken in an attempt to further delineate the localization and nature of the metals in question.
The Journal of Comparative Neurology, 1991
A detailed description is given of the distribution of zinc in three areas of the domestic pig hippocampal region, viz., the entorhinal area, the parasubiculum, and the presubiculum. Zinc was demonstrated histochemically with use of the Neo-Timm method, a recent modification of the sulphide silver procedure. Each of the studied areas showed a distinctly stratified staining pattern, which has been correlated in detail to fields and layers defined on the basis of cyto-and fibroarchitecture, providing a combined chemo-and cytoarchitectonic map. The staining was primarily confined to the neuropil, although stained nerve cell bodies were encountered in all three parts of the hippocampal region. Two main subfields were identified in the entorhinal area that have been designated pars medialis and pars lateralis, in accordance with their topographical positions, but both the cytoarchitecture and Neo-Timm staining pattern are indicative of further subdivision. In pars medialis, the deep half of layer I, the interstices between the stellate cell bodies in layer 11, and layer I11 were medium to heavily stained, whereas layer IV stained weakly. Layers V-VI were slightly darker than layer IV and were inseparable on the basis of the Neo-Timm staining. The staining of pars lateralis differed in many respects from that of pars medialis, the most conspicuous feature being a much lighter layer 111. In the parasubiculum, the deep half of layer I together with layers 11-111 had the appearance of an intensely stained triangle wedged in between the entorhinal area and the presubiculum. The latter showed moderate staining of the inner half of layer I and posterior part of layer 11, while layer IV was stained intensely. Layers I11 and V-VI exhibited only weak staining. The distribution of zinc in the pig was compared with that in the guinea pig and rat, described previously. Although many histochemical features are shared by the staining patterns of the three species, striking differences exist in the pig, the most notable being the virtually reverse staining of the entorhinal layer IV. The possible functional implications of zinc in synaptic vesicles are considered.
Histochemistry, 1985
From rats intravitally treated with dithizone (diphenyl-thiocarbazone) brains and spinal cords were removed and freeze-dried. The dithizonates present in the CNS tissue were extracted with carbon tetrachloride and subjected to a multielement analysis (proton activation, PIXE). It was found that the extract contained two metals. Most of the metal was zinc, but small traces of copper were also detected. Because prior treatment with the chelating agent, dithizone, can block both the Timm and the selenium metal staining methods, it is suggested that the three techniques label predominantly zinc in the neuropil (DTS-zinc).
Distribution of histochemically reactive zinc in the forebrain of the rat
Journal of Chemical Neuroanatomy, 1992
The nlajor cytoarchitectonic regions of the rat brain that stain with the Timm l)anscher metal slain ~ere tested with the flourescent probe for zinc, 6-methoxy 8-para toluene sulfonamide quinoline (ISQ). Throughout most of the striatum, cerebral cortex and limbic system, tile diffuse, even neuropil staining produced by the Timm Danscher method was mirrored by comparable fluorescence in TSQ-stained sections. Blockade of the TSQ fluorescence by prior treatment with sulphide indicated that tile limm Danschcr and tile TSQ procedures both labeled the same pool of endogenous metal, which is in fcrrcd to bc tile zinc that is in axonal boutons. It is concluded that the Tilnm l)anscher staining generally indicates zinc-containing axonal boutons. Tile distribution of the zinc-containing axonal boutons throughout the forcbram is described.
Brain Research, 1977
Okamoto 17 introduced dithizone (diphenylthiocarbazone) as a histochemical technique for the demonstration of zinc. Dithizone forms coloured complexes with a number of transition metals and group lib metals, and was found by Kadota 14 and Stampfl et al. z° to produce a reddish stain when administered intravitally. Maske 15 first demonstrated zinc in the mammalian hippocampus by means of spectrophotometry of the coloured zinc-dithizone complex. The details of the distribution of the red chelate in this region has been described by Fleischhauer and Horstmannll; and McLardy 16 demonstrated that the heavily stained region coincides with the hilus of the fascia dentata and the layer of mossy fibers (see also .
Stable-isotope dilution measurement of zinc and lead in rat hippocampus and spinal cord
Brain Research, 1982
Key words zinc --lead --hlppocampus --stable-isotopes --rat Zinc and lead concentrations m hippocarnpus and spinal cord of rats were measured using the highly-accurate method of stable isotope dflunon mass-spectrometry In hlppocampus, average zinc concentratmn was 72 7 ppm (dry weight), average lead, 0 053 ppm, m spinal cord, zme averaged 26 1 ppm, lead, 0 018 ppm Possible explanations for apparent overesttmanons of rat CNS metal content m prewously pubhshed work were dmcussed
The neurotoxicity of zinc in the rat hippocampus
Neuroscience Letters, 1990
Intrahippocampal injections of zinc chloride (5-10 nmol) caused a discrete lesion in the rat hippocampus, involving all neuronal perikarya. In addition to the necrosis, the lesion was also characterized by a decrease in staining of the neuropil, the presence of pyknotic neurons, and occasionally infarction. Pathological changes occurred within 8 h of an injection, and neuronal loss, as judged by the loss of Nissl staining, was complete within 24 h. On the other hand, the loss of acidophilic staining of the neurons was more gradual, as acid fuchsin staining was still present in neurons in the periphery of the damaged area 4 days later. In comparison with an excitotoxic lesion, glial infiltration into the damaged area was minimal, even up to 3 weeks later, suggesting that some glial cell toxicity also occurred.