1998 Fiscal Year Final Research Report Summary
Development of quantitative autoradiographic method for assessing fuctional imaging in living brain slices.
| Project/Area Number |
09557189
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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 |
Physical pharmacy
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| Research Institution | KYOTO UNIVERSITY |
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Principal Investigator |
SAJI Hideo Kyoto University, Graduate School of Pharmaceutical Sciences, Professor, 薬学研究科, 教授 (40115853)
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| Co-Investigator(Kenkyū-buntansha) |
MORI Kennji Fuji Photo Film Co., Ltd., Equipment Products Div., Enginnering Associate, 機器事業部, 主任技師
MAGATA Yasuhiro Kyoto University, Graduate School of Medicine, Assistant Professor, 医学研究科, 助手 (20209399)
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| Project Period (FY) |
1997 – 1998
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| Keywords | brain / Bio-Imaging Analyzer / imaging plate / living slice / radiolabeled ligand / glucose metabolism / hypoxia / central benzodiazepine receptors |
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| Research Abstract |
Bio-Imaging Analyzer System with imaging plate was recently developed and possesses with ultra high sensitivity, high resolution and a wide dynamic range compared with X-ray films. Taking advantages of the Bio-Imaging Analyzer System, we examined the possibility of applying this system for functional imaging in living brain slices. Whole brain slices of 300 mum thickness were incubated with radiolabeled compounds. The slices were then rinsed and placed on the bottom of a Plexiglas chamber filled with Krebs.Ringer solution. The bottom of the chamber consisted of a thin polypropylene film to allow good penetration of radiation from the brain slices. The chamber was placed on a imaging plate. After exposure, the imaging plate was scanned by the Bio-Imaging Analyzer System and radioactivity images of brain slices were obtained. By using this system, we evaluated the glucose metabolism changes under hypoxic condition and the super high affinity binding sites in rat hippocampus for [3-H]Ro 1
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5-4513, a partial inverse agonist of central benzodiazepine receptors. Under hypoxic condition, increase of radioactivity of [14-C]glucose was observed in all brain regions compared with the control group. Differences of increase rate of rdioactivity uptake between brain regions were also observed. These results suggested that utilization rate of glucose increase due to acceleration of anaerobic metabolism and that energy demands vary depending on the brain regions under hypoxic condition compared with control group. On the other hand, in vitro binding of [3-H]Ro15-4513, the supar high affinity binding sites in the hippocampus were observed when the [3-H]Ro15-4513 concentration was below 0.5 nM.In vivo, the supar high affinity binding sites were only found when the injected dose of Ro15-4513 was below 3.6 mug/kg and almost disappeared when the dose was increased to 10 mug/kg. These results both in vitro and in vivo indicate that there is a significant discrepancy between actual free ligand concentration in vivo and in vitro, and that concntration in intact brain may be much lower than previously thought. Less
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