コカインの繰り返し暴露は,中脳ドーパミンニューロンにおけるLTP誘導を促進します
Qing-song Liu1, Lu Pu, Mu-ming Poo
1Division of Neurobiology, Department of Molecular and Cell Biology, Helen Wills Neuroscience Institute, University of California, Berkeley, California 94720, USA. qsliu@berkeley.edu
Nature
|October 14, 2005
まとめ
コカインを繰り返し摂取すると,GABA (A) 受容体の阻害を減らし,腹部帯膜領域 (VTA) のドーパミンニューロンにおけるシナプス可塑性を高めます. これにより,長期増強 (LTP) が促進され,薬物関連記憶形成に潜在的に役立ちます.
科学分野:
- 神経科学は神経科学である.
- 神経薬理学神経薬理学について
- 依存症の研究 依存症の研究
背景:
- 薬物乱用薬は神経回路を変化させ,中毒を引き起こす.
- ベントラル・テグメンタル・エリア (VTA) ドーパミンニューロンのシナプス可塑性は,薬物誘発の回路改変に関与しています.
研究 の 目的:
- ネズミのVTAドーパミンニューロンにおけるシナプス可塑性に対するコカインの繰り返し曝露の影響を調査する.
- コカイン誘発のシナプス変化におけるGABA (A) 受容体媒介阻害の役割を決定する.
主な方法:
- ネズミの体内でのコカインの繰り返し投与.
- 長期増強 (LTP) 誘導を評価するために,中脳スライスにおける電気生理学的記録.
- ビキュキュリン,ピクロトキシン,ディアゼパムを使用したGABA (A) 受容体の活性に対する薬理学的操作.
主要な成果:
- コカインを繰り返し摂取すると,VTAのドーパミンニューロンへの刺激性シナプスでLTP誘導が促進される.
- この促進は,コカイン誘発によるGABA (A) 受容体媒介抑制の減少と関連していた.
- 強化されたGABAergic阻害は,コカイン誘発のLTPを予防しましたが,素朴なネズミの誘発には抑制の低下が必要でした.
- コカイン治療はGABA媒介のシナプス電流の振幅を低下させ,VTAドーパミンニューロンにおけるスパイク開始確率を増加させた.
結論:
- コカインを繰り返し摂取すると,VTAのドーパミンニューロンにおけるシナプス可塑性が向上する.
- 減少したGABA (A) 受容体阻害は,この可塑性増強の基礎となる重要なメカニズムです.
- コカインによって引き起こされるVTAシナプス可塑性は,薬物に関連した記憶の形成に役割を果たす可能性があります.
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