プレシナプス活動は,軸索の初期セグメントのNa(+) チャンネル分布を調節する
Hiroshi Kuba1, Yuki Oichi, Harunori Ohmori
1Career-Path Promotion Unit for Young Life Scientists, Kyoto University Graduate School of Medicine, Kyoto 606-8501, Japan. kuba@nbiol.med.kyoto-u.ac.jp
Nature
|June 15, 2010
まとめ
感覚的欠乏は,軸索初期セグメント (AIS) の延長を引き起こし,ニューロンの興奮性を増加させます. AISにおけるこのホメオスタティックな可塑性は,難聴後の聴覚機能を維持するのに役立ちます.
科学分野:
- 神経科学は神経科学である.
- 細胞神経科学は細胞神経科学である.
- 聴覚神経科学とは
背景:
- 神経回路は,アファレントの入力を奪われたときに活動を回復するための可塑性を発揮します.
- アクソン初期セグメント (AIS) は神経信号の開始に不可欠ですが,既知の可塑性がない.
- ホメオスタティック調節は,変化する条件下で神経機能を維持するために不可欠です.
研究 の 目的:
- 感覚的欠乏に対する反応として,AISがプラスチックの変化を経験するかどうかを調査する.
- AISの可塑性がニューロンの興奮調節に寄与するかどうかを判断する.
- 難聴後の神経機能の維持におけるAISの可塑性の役割を調査する.
主な方法:
- 鳥類の脳幹の聴覚ニューロンにおける聴覚入力欠乏.
- AISの長さを測定し,電圧ゲートされたNa ((+)) チャンネルとAISのアンカリングタンパク質の分布を測定します.
- 細胞全体のNa ((+) 流,膜刺激性,自発発火速の評価.
主要な成果:
- オーディトリー・インプットの欠乏により,AISの長さは7日以内に1.7倍に増加しました.
- AISの長さの増加は,全細胞のNa (((+) 流と膜刺激性の向上と関連していました.
- 聴覚の入力を奪われた後,自発的なニューロンの発火率も増加した.
結論:
- 軸索の初期セグメント (AIS) は,感覚的欠乏に反応して延長され,ホメオスタティックな可塑性を示す.
- AISの可塑性はニューロンの興奮性を高め,潜在的に失われた感覚入力を補償します.
- スパイク開始部位の可塑性は,感覚喪失の間に神経計算の精錬のためのメカニズムを提供します.
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