2001 Fiscal Year Final Research Report Summary
Positron imaging of water, ion, and trace metals in living tissue in vitro
| Project/Area Number |
11557002
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 展開研究 |
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| Research Field |
General physiology
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| Research Institution | KYOTO UNIVERSITY |
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Principal Investigator |
MATSUMURA Kiyoshi Kyoto Univ., Grad. Sch. Informatics, Associate Prof., 情報学研究科, 助教授 (10157349)
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| Co-Investigator(Kenkyū-buntansha) |
KOBAYASHI Shigeo Kyoto Univ., Grad. Sch. Informatics, Prof., 情報学研究科, 助教授 (40124797)
SUZUKI Kazutoshi National Institute for Radiological Sciences, Unit leade, 放射線医学総合研究所, ユニットリーダー
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| Project Period (FY) |
1999 – 2000
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| Keywords | Positron / Brain slice / Potassium ion / Na^+-K^+ pump / tetrodotoxin / 乳酸 / ピルビン酸 |
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| Research Abstract |
1. Using ^<38>K^+, a positron emitting nuclide, as a tracer, we succeeded to make imaging of ^<38>K^+ uptake in living brain slices from rats.
2. Brain slices took up ^<38>K^+ in a time-dependent manner. The uptake was relatively high in the forebrain and low in the cerebellum, pons and medulla.
3. ^<38>K^+ was almost completely suppressed by ouabain treatment indicating that ^<38>K^+ uptake represents the activity of Na^+/K^+ pump.
4. ^<38>K^+ was further enhanced by co-incubation of nonspecific K^+ channel blocker, Ba^<2+>. This is likely due to the inhibition of outward flow of ^<38>K^+, which had been taken up by Na^+/K^+ pump.
5. Tetrodotoxin, a Na^+ channel blocker, did not affect the uptake of ^<38>K^+, suggesting the uptake represents the activity of Na^+/K^+ pump which activity is not influenced by neuronal activity very much.
6. Depletion of glucose for 4 hours almost completely abolished the ^<38>K^+ uptake. Mono-carboxylic acids, lactate or pyruvate, in the absence of glucose partially maintained the ^<38>K^+ uptake, indicating that these monocarboxylic acids can be the energy substrate in the brain slices. Other organic acids, including fatty acids, will be investigated for their ability to drive Na^+/K^+ pump.
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