Inorganic Cations in Rat Kidney

Abstract

For localization of pyroantimonate-precipitable cations, rat kidney was fixed by perfusion with a saturated aqueous solution of potassium pyroantimonate (pH about 9.2, without addition of any conventional fixative) . A remarkably good preservation of the tissue and cell morphology was obtained as well as a consistent and reproducible localization of the insoluble antimonate salts of magnesium, calcium, and sodium . All proximal and distal tubules and glomeruli were delimited by massive electron-opaque precipitates localized in the basement membrane and, to a lesser extent, in adjacent connective tissue . In the intraglomerular capillaries the antimonate precipitate was encountered in the basement membranes and also between the foot processes . In addition to a more or less uniform distribution in the cytoplasm and between the microvilli of the brush border, antimonate precipitates were found in all cell nuclei, mainly between the masses of condensed chromatin . The mitochondria usually contained a few large antimonate deposits which probably correspond to the so-called "dense granules" observed after conventional fixations .

Reversibly contractile nuclear matrix. Its isolation, structure, and composition.

“…However, we are unable to determine whether this is due to reversible contraction of the matrix equivalent in these macronuclei or to possible swelling and contraction of the nuclear chromatin. On the other hand, Ca and Mg are accumulated more in the cell nucleus than in the cytoplasm in vivo (26,29). In rat liver cells, for example, the nuclear Ca/Mg concentration can be approximated to be -25 mM (for review see reference 25).…”

Biological Calcification

“…In the mitochondria of normal tissues, granules appear to be especially plentiful when specimens are processed by freezing methods (Ali and Wisby 1975;Landis et al 1977b;Landis and Glimcher 1982;Manston and Katchburian 1983;Takano et al 1989), are prepared anhydrously (Landis et al 1977a(Landis et al , 1980, or are treated with potassium pyroantimonate (Tandler and Kierszenbaum 1971;Schäfer 1973;Brighton and Hunt 1974Burger and Matthews 1978;Morris and Appleton 1980;Silbermann 1982, 1990;Kogaya and Furahashi 1988). In the mitochondria of normal tissues, granules appear to be especially plentiful when specimens are processed by freezing methods (Ali and Wisby 1975;Landis et al 1977b;Landis and Glimcher 1982;Manston and Katchburian 1983;Takano et al 1989), are prepared anhydrously (Landis et al 1977a(Landis et al , 1980, or are treated with potassium pyroantimonate (Tandler and Kierszenbaum 1971;Schäfer 1973;Brighton and Hunt 1974Burger and Matthews 1978;Morris and Appleton 1980;Silbermann 1982, 1990;Kogaya and Furahashi 1988).…”

Inorganic Cations in the Cell Nucleus

“…The fixative used was a saturated aqueous solution of potassium pyroantimonate (Riedel-De Haen AG, Seelze, Hanover, Germany, analytical reagent) freshly prepared by boiling the salt in twice glassdistilled water, cooling rapidly to room temperature, and centrifuging (pH about 9 .2) . After fixation-as described above-the testis was hardened with formaldehyde, postosmicated and washed with three changes of distilled water as described before (4,5) . Afterwards, the tissues were dehydrated with graded concentrations of cold ethanol, passed through propylene oxide, and embedded in Maraglas (The Marblette Company, Div .…”

“…Thin sections of pyroantimonate-fixed tissues cannot 484 THE JOURNAL OF CELL BIOLOGY • VOLUME 53, 197 be stained with the usual uranyl acetate and lead citrate procedures unless the grids are treated with oxalic acid : simultaneous staining and removal of antimonate deposits are obtained, as described previously (5) . In the present study, this procedure was modified in that staining also can be achieved almost without removal of antimonate precipitates, by simply lowering the oxalic acid concentration (one volume of a saturated solution in 400 vol of distilled water) .…”

“…A more accurate knowledge of intranuclear ionic conditions, particularly in response to different cell events, should provide an indication if means were at hand to localize them . A method recently has been developed which allows the visualization of inorganic cations (except K+) at their cellular and subcellular locations with the electron microscope (4,5) . One constantly observed result was, indeed, the presence of a significant accumulation of inorganic cations (Mg++, Ca++, and Na+) in the nucleus, the amount and intranuclear distribution of which varied in several tissues .…”