| Project/Area Number |
10558107
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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 |
Biophysics
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| Research Institution | The University of Tokyo |
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Principal Investigator |
KAWATO Suguru The University of Tokyo, Graduate School of Arts and Sciences, Professor, 大学院・総合文化研究科, 教授 (50169736)
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| Co-Investigator(Kenkyū-buntansha) |
TANAAMI Takeo Takeo Yokogawa Electric, Center for development project, Chief (Researcher), 係長(研究職)
KIMOTO Tetsuya The University of Tokyo, Graduate School of Arts and Sciences, Research Associate, 大学院・総合文化研究科, 助手 (60292843)
田名網 健夫 横河電気, 開発プロジェクトセンター, 係長
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| Project Period (FY) |
1998 – 2000
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| Project Status |
Completed (Fiscal Year 2001)
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| Budget Amount *help |
¥13,400,000 (Direct Cost: ¥13,400,000)
Fiscal Year 2000: ¥2,000,000 (Direct Cost: ¥2,000,000)
Fiscal Year 1999: ¥3,900,000 (Direct Cost: ¥3,900,000)
Fiscal Year 1998: ¥7,500,000 (Direct Cost: ¥7,500,000)
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| Keywords | confocal microscopy / neurosteroid / glia / neuron / Ca signal / 共焦点ビデオ顕微鏡 / 対物レンズスキャン / 3次元分布 / 海馬スライス / 培養細胞 |
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| Research Abstract |
We constructed a real time scanning confocal microscopy system. This system enables gaining real-time serial confocal images by scanning the objective lens vertically. We carried out following experiments to evaluate its function. Upon mechanical stimulation using glass micropipette, Ca^<2+> signal was generated in a single astroglial cell. Radial propagation of Ca^<2+> wave across cultured astrocytes was observed. The Ca^<2+> wave reached a neuron in the fringe of astrocyte layer. Also Ca^<2+> signal from a mechanically stimulated neuron could elicit Ca^<2+> wave on the astrocyte layers. Thus, we indicated bi-derectional propagation of Ca^<2+> signals between cultured neurons and astrocytes with improved spatial resolution compared to conventional microscopy system. Next, we investigated a modulatory effect of a neurosteroid, pregnenolone sulfate (PREGS), on Ca^<2+> signal mediated by NMDA receptor in CA1 neurons of acute hippocampal slices after 20 min incubation with PREGS. Ca^<2+>-sensitive fluorescent dye Fura-2 was introduced in hippocampal neurons. Intracellular Ca^<2+> rise through NMDA receptor was doubled with 100 M PREGS, leading significant up-regulation of synaptic transmittion efficiency.
Also we are studying synthesis of neuroteroids and found that activity-dependent Ca^<2+> signals in hippocampal neurons could facilitate the synthesis of PREGS. Our results revealed a positive feedback system of neural transmittion; Ca^<2+> signal by neural activity induces the synthesis of PREGS from cholesterol→secreted PREGS enhances Ca^<2+> signal by NMDA receptors→facilitation of synaptic transmittion. we are currently proposing a novel concept of local synthesis and acute action of neurosteroids.
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