ISSN:
1432-0827
Keywords:
Marrow stromal cells
;
Dexamethasone
;
Alkaline Phosphatase
;
Calcium channels
;
Differentiation
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
,
Medicine
,
Physics
Notes:
Abstract The production of biochemical markers associated with the osteoblastic phenotype, and accompanying changes in the expression of voltage-operated Ca2+ channels, have been examined in rat bone marrow stromal cell cultures treated with dexamethasone (10-8 M). Whole cell clamp analysis of voltage-operated Ca2+ channels in control cultures (using Ba2+ as the charge carrier) revealed primarily a high voltage-activated (HVA), slowly inactivating current, which was enhanced two- to threefold by treatment of the cells with Bay K 8644 (300 nM) and inhibited by nifedipine (4 μM). In dexamethasone-treated cultures, the I–V relationship for inward current was shifted to more positive potentials in comparison with control cells. Most cells in these cultures possessed both the HVA current and also a faster inactivating, low-voltage-activated (LVA), nifedepineresistant current. These two currents could be separated both by nifedipine and by the use of steady state inactivation of the LVA current. The two components of the Ba2+ current varied widely in their relative size. The combination of LVA and HVA currents seen in dex-induced stromal cells resembles records of voltage-operated Ca2+ channels from cultures of calvarial osteoblasts.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00296063
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