Na+-Ca2+交換器媒介のCa2+が心筋細胞に流入することで生じる有害なバイオエネルギー効果
Michael Kohlhaas1, Christoph Maack
1Universitätsklinikum des Saarlandes, Klinik für Innere Medizin III, 66421 Homburg, Germany.
Circulation
|November 25, 2010
まとめ
心不全では,ナトリウム-カルシウム交換器 (NCX) がミトコンドリアのカルシウム吸収を阻害し,故障している心臓のエネルギー飢餓を引き起こす可能性があります. これは細胞のエネルギー生産と心臓の機能に影響を及ぼします.
科学分野:
- 心臓病学 心臓病学
- 細胞生理学 細胞生理学
- ミトコンドリア生物学
背景:
- 心不全では,ナトリウム・カルシウム交換器 (NCX) が上調され,カルシウム流入を媒介する.
- このNCX活動は,考慮されていないエネルギー上の影響を及ぼす可能性があります.
- エネルギー生産に不可欠なミトコンドリアのカルシウム吸収は,カルシウム梯度に依存しています.
研究 の 目的:
- ミトコンドリアのバイオエネルギー学に対するNCX媒介カルシウム流入の影響を調査する.
- NCXの活性がミトコンドリアカルシウム吸収の効率とクレブス循環の活性に影響するかどうかを判断する.
主な方法:
- 豚のミオサイトでパッチクランプ技術を使用して,シトソリックおよびミトコンドリアカルシウムを測定しました.
- L型カルシウムチャネル (I ((Ca,L)) とNCX) 経由で多様なカルシウム流入が行われます.
- ミトコンドリアカルシウム吸収効率の評価は,移行期間のミトコンドリアカルシウムとシトソリックカルシウムをプロットすることによって行われます.
主要な成果:
- ミトコンドリアカルシウム吸収効率は,I ((Ca,L)) 誘発カルシウム放出時に最大でした.
- サルコプラズマ網膜のカルシウム負荷の減少とNCXの活性度の増加は,ミトコンドリアのカルシウム吸収効率を低下させた.
- サイトソリックカルシウムの一時的な上昇速度は,ミトコンドリアカルシウム吸収効率と相関しています.
- NCX媒介のカルシウム流入は,サルコプラズマ網膜の放出とは異なり,クレブス周期脱水酸化を刺激しなかった.
結論:
- 心不全における細胞性カルシウムトランジエントに対するNCXの寄与の増加は,ミトコンドリアのカルシウム吸収を損なう.
- この吸収の低下は,バイオエネルギーフィードバック応答に悪影響を及ぼします.
- このメカニズムは,心不全で観察されるエネルギー飢餓に寄与する可能性があります.
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