リラクゼーション中の急速な縮小は,活性化を増加させ,シストリックパフォーマンスを改善します
M W Watkins1, A Higashiyama, Z Chen
1Cardiology Unit, University of Vermont, Burlington 05401, USA.
Circulation
|September 15, 1996
まとめ
シストルの後のエジェクションは,終末ダイアストリック容量とは無関係に心臓の収縮性を高めます. この効果は,特に急速な放出では,活性化のためにカルシウムが利用可能になり,心室の性能が向上することを示唆しています.
科学分野:
- 心血管生理学 心血管の生理学
- 心臓のメカノエネルギー学
- 静脈の機能 静脈の機能 静脈の機能
背景:
- 以前の研究では,長さ依存の活性化にポジティブなエジェクション効果がしばしば起因していた.
- いくつかの研究では,エンド・ダイアストリック・ボリューム (EDV) の履歴から独立して,エジェクション関連の収縮強化が示されました.
- 現在の研究は,無傷な心室におけるこれらの放出独立のメカノエネルギー効果を明らかにすることを目的とした.
研究 の 目的:
- 射出独立の収縮強化のメカノエネルギー的結果を特徴づけるために.
- 快速体積減少 (VR) が心室の機能に与える影響を調査する.
- 放出,カルシウム循環,酸素消費の関係を探求する.
主な方法:
- 隔離されたウサギの心臓は,左心室の制御された体積減少 (VR) のためのサーボモーターを使用して,シストールの終わりに研究されました.
- 実験には,同体積収縮,遅いVR (5.0 +/- 0.9EDV/s),および恒定EDVで急速VR (26.8 +/- 5.1EDV/s) が含まれていた.
- 左心室の酸素消費量 (VO2) と非機械的VO2 (2,3-ブタンジオンモノキシムを用いて) を測定した.
主要な成果:
- ボリュームリダクション (VR) は,イソボリュームビートと比較して,著しく収縮性を高め,急速なVRでより大きな効果を示した.
- ラピッドVRは発達圧を15%,最大dP/dtを17%,エマックスを13% (P < .01) 増加させた.
- ラピッドVRはVO2を全体的に8%減少させ,非機械的VO2を26%増加させ,カルシウム循環の増加を示唆した.
結論:
- 筋収縮後のエジェクションは,長さ依存の活性化を超えて心室の性能に肯定的な影響を及ぼします.
- この発見は,放出時に活性化するために利用可能なカルシウムの増加を示唆しています.
- 射出は,ミオフィラメントの縮小とアクティベーターカルシウムサイクルと正の相互作用があるようです.
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