Cu(II) and Zn(II) ions alter the dynamics and distribution of Mn(II) in cultured chick glial cells
- Dept. of Molecular Cell Biology, Pennsylvania State University, University Park (USA)
Previous studies revealed that Mn(II) is accumulated in cultured glial cells to concentrations far above those present in whole brain or in culture medium. The data indicated that Mn(II) moves across the plasma membrane into the cytoplasm by facilitated diffusion or counter-ion transport with Ca(II), then into mitochondria by active transport. The fact that 1-10 microM Mn(II) ions activate brain glutamine synthetase makes important the regulation of Mn(II) transport in the CNS. Since Cu(II) and Zn(II) caused significant changes in the accumulation of Mn(II) by glia, the mechanisms by which these ions alter the uptake and efflux of Mn(II) ions has been investigated systematically under chemically defined conditions. The kinetics of (54MN)-Mn(II) uptake and efflux were determined and compared under four different sets of conditions: no adducts, Cu(II) or Zn(II) added externally, and with cells preloaded with Cu(II) or Zn(II) in the presence and absence of external added metal ions. Zn(II) ions inhibit the initial velocity of Mn(II) uptake, increase total Mn(II) accumulated, but do not alter the rate or extent Mn(II) efflux. Cu(II) ions increase both the initial velocity and the net Mn(II) accumulated by glia, with little effect on rate or extent of Mn(II) efflux. These results predict that increases in Cu(II) or Zn(II) levels may also increase the steady-state levels of Mn(II) in the cytoplasmic fraction of glial cells, which may in turn alter the activity of Mn(II)-sensitive enzymes in this cell compartment.
- OSTI ID:
- 5505153
- Journal Information:
- Neurochemical Research; (United States), Vol. 15:12; ISSN 0364-3190
- Country of Publication:
- United States
- Language:
- English
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59 BASIC BIOLOGICAL SCIENCES
COPPER
METABOLISM
MANGANESE
ZINC
CELL MEMBRANES
CHICKENS
CYTOPLASM
MANGANESE 54
MEMBRANE TRANSPORT
NERVE CELLS
TRACER TECHNIQUES
ANIMAL CELLS
ANIMALS
BETA DECAY RADIOISOTOPES
BIRDS
CELL CONSTITUENTS
DAYS LIVING RADIOISOTOPES
ELECTRON CAPTURE RADIOISOTOPES
ELEMENTS
FOWL
INTERMEDIATE MASS NUCLEI
ISOTOPE APPLICATIONS
ISOTOPES
MANGANESE ISOTOPES
MEMBRANES
METALS
NUCLEI
ODD-ODD NUCLEI
RADIOISOTOPES
SOMATIC CELLS
TRANSITION ELEMENTS
VERTEBRATES
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