2019 Fiscal Year Final Research Report
Analysis of respiratory center in newborn rat by optogenetics
| Project/Area Number |
16K07003
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Multi-year Fund |
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| Section | 一般 |
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| Research Field |
Neurophysiology / General neuroscience
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| Research Institution | Showa University |
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Principal Investigator |
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| Project Period (FY) |
2016-04-01 – 2020-03-31
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| Keywords | Phox2b / 呼吸リズム / トランスジェニックラット / オプトジェネティクス / チャネルロドプシン / アーチロドプシン |
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| Outline of Final Research Achievements |
We developed a transgenic (Tg) rat line in which Phox2b-positive cells expressed archaerhodopsin-3 (Arch) or the step-function channelrhodopsin variants (ChRFR) under the control of Phox2b promoter-enhancer regions. We analyzed a local neuron network of the respiratory center in the medulla of a brainstem-spinal cord preparation isolated from 0-2-day-old Tg rat. The photostimulation induced inhibition or facilitation of the respiratory rhythm in Arch-expressing or ChRFR-expressing Tg rats, respectively. Phox2b-positive Pre-I neurons were hyperpolarized or depolarized in Arch-expressing or ChRFR-expressing Tg rat preparations, respectively. The photostimulation induced heterogeneous membrane potential changes of other respiratory-related neurons, depending on properties of synaptic connections (especially between Pre-I neurons) in the respiratory center. The optogenetic approach was a powerful method of verifying a hypothetical model of local networks among respiratory-related neurons.
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| Free Research Field |
神経生理学
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| Academic Significance and Societal Importance of the Research Achievements |
本研究では，非スライスin vitro 脳標本である新生児ラット脳幹―脊髄標本を用いた．これはオプトジェネティクスによる呼吸中枢神経回路の解析としては世界で初めての試みとなった．摘出脳幹標本は，Cre-loxP システムを用いた遺伝子組み換えによって，Phox2b 遺伝子の発現制御領域下に光感受性チャネル（アーキロドプシンおよびチャネルロドプシン）を発現させた新生児ラット（生後０－２日）から摘出した．光感受性チャネルを選択的に光刺激することによって引き起こされる呼吸リズムの変化，呼吸性ニューロンの膜電位変化などを詳細に解析することで，呼吸中枢の神経回路の動作特性が明瞭に示すことができた．
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