| Project/Area Number |
05807172
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
Functional basic dentistry
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| Research Institution | NAGASAKI UNIVERSITY |
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Principal Investigator |
OKADA Yukio NAGASAKI UNIVERSITY SCHOOL OF DENTISTRY,DEPT OF PHYSIOLOGY,ASSOCIATE PROFESSOR, 歯学部, 助教授 (60136687)
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| Project Period (FY) |
1993 – 1994
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| Project Status |
Completed (Fiscal Year 1994)
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| Budget Amount *help |
¥2,000,000 (Direct Cost: ¥2,000,000)
Fiscal Year 1994: ¥400,000 (Direct Cost: ¥400,000)
Fiscal Year 1993: ¥1,600,000 (Direct Cost: ¥1,600,000)
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| Keywords | Rat / Osteoclast / Patch-clamp technique / Bone marrow cells / Proton pump |
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| Research Abstract |
Wister rat pups (up to 1 week old) were used for the experiments. Femora and tibiae were removed from four pups anesthetized with Nembutal and were split longitudinally. Soft tissue was removed from bones, which were then dispersed by repeated passage through a Pasteur pipette. Cell suspension (0.004ml) was placed on a glass coverslip coated with fibronectin and were incubated at 30ﾟC for 60 min. I found the two morphological categories of osteoclasts observed during this study. One was composed of well-spread, flattened cells ( "spread" osteoclast). The second category of the cells consisted of dome-shaped ( "rounded" osteoclasts). Both "spread" and "rounded" osteoclasts stained positive for tartrate-resistant acid phosphatase (TRAP).
Membrane properties of isolated rat osteoclasts were examined using whole-cell mode of the patch-clamp technique. "Spread" osteoclast had resting potentials from -10 to -80 mV,input resistances from 1 to 10 GOMEGA and membrane capacities from 10 to 55 pF.
… More
The spread cells displayd an inward current in response to hyperpolarizing voltage steps and little outward current in response to depolarizing voltage steps.The inward current was similar in its voltage dependence of activity and its sensitivity to blockade by extracellular Ba^<2+> and Cs^+ to the inward rectifying K^+ current. In a few cases, The current was a little inhibited by DCCD which is the inhibitor for the proton-pump. The "rounded" osteoclast had resting potentials from -30 to -60 mV,input resistances from 2 to 8 GOMEGA and membrane capacities from 10 to 100 pF.The rounded cells displayd only leak components of current in the voltages more negative than the resting potential, while the cells exhibited a large outward current in the voltages more positive than the resting potential. The outward current was inhibited by external Ba^<2+> and DCCD.13EA03 : Although the present study identified the current components decreased by DCCD,an inhibitor for the proton pump, the DCCD-inhibitable component may be K^+ currents. Further experiments in which H^+ current without K^+ current can be detectable must be carried on. Less
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