| Project/Area Number |
16500205
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Neuroscience in general
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| Research Institution | JICHI MEDICAL SCHOOL |
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Principal Investigator |
IKEDA Keiko JICHI MEDICAL SCHOOL, School of Medicine, Associate Professor, 医学部, 助教授 (10265241)
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| Co-Investigator(Kenkyū-buntansha) |
KAWAKAMI Kiyoshi JICHI MEDICAL SCHOOL, School of Medicine, Professor, 医学部, 教授 (10161283)
ONIMARU Hiroshi Showa University, Associate Professor, 医学部, 助教授 (30177258)
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| Project Period (FY) |
2004 – 2005
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| Project Status |
Completed (Fiscal Year 2005)
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| Budget Amount *help |
¥3,600,000 (Direct Cost: ¥3,600,000)
Fiscal Year 2005: ¥1,800,000 (Direct Cost: ¥1,800,000)
Fiscal Year 2004: ¥1,800,000 (Direct Cost: ¥1,800,000)
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| Keywords | Sodium pump / Alpha2 subunit / Knockout mouse / Brainstem / Respiratory neuron / Chloride ion / KCC2 / GABA / ナトリウムポンプ / α2アイソフォーム / 呼吸中枢神経系 / 摘出脳幹脊髄標本 / クロライドイオン濃度 |
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| Research Abstract |
Na^+, K^+-ATPase (Sodium pump) alpha2 subunit gene (Atp1a2) knock-out homozygous mice (Atp1a2^<-/->) died immediately after birth resulting from lack of breathing. The respiratory-related neuron activity in Atp1a2^<-/-> was investigated using a brainstem-spinal cord en bloc preparation. The respiratory motoneuron activity recorded from the fourth cervical ventral root (C4) was defective in Atp1a2^<-/-> fetuses of embryonic day 18.5. The C4 response to electrical stimulation of the ventrolateral medulla (VLM) recovered more slowly in Atp1a2^<-/-> than in wild type during superfusion with Krebs' solution, consistent with the high extracellular GABA in brain of Atp1a2^<-/->. Lack of inhibitory neural activities in VLM of Atp1a2^<-/-> was observed by optical recordings. High intracellular Cl^- concentrations in neurons of the VLM of Atp1a2^<-/-> were detected in gramicidin-perforated patch-clamp recordings. The alpha2 subunit and a neuron-specific K-Cl cotransporter KCC2 were coimmunoprecipitated in a purified synaptic membrane fraction of wild-type fetuses. Based on these results, we propose a model for functional coupling between the Sodium pump alpha2 subunit and KCC2, which excludes Cl^- from the cytosolin respiratory center neurons. These results indicate that alpha2 subunit harbor a unique function that is not compensated by alphal subunit which express in the same neurons.
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