閉塞性心不全患者の運動に対するクロノトロピック応答の低下. ポストシナプスベータアドレナジック脱敏感化の役割
W S Colucci1, J P Ribeiro, M B Rocco
1Department of Medicine, Brigham and Women's Hospital, Boston, MA 02115.
Circulation
|August 1, 1989
まとめ
閉塞性心不全 (CHF) の患者は,運動に対する心拍数 (HR) の鈍化反応を示します. これは,ベータアドレナゲン受容体の感受性の低下によるもので,ノルエピネフリン濃度の変化によるものではない可能性が高い.
科学分野:
- 心臓病学 心臓病学
- 運動生理学 運動生理学
- 薬理学 薬理学とは
背景:
- 閉塞性心不全 (CHF) の患者は,運動中に心拍数 (HR) 応答の弱まりを示することが多い.
- CHFにおけるこの運動 HR 応答の減少の基礎となる生理学的メカニズムは完全に理解されていません.
研究 の 目的:
- 心臓発作の患者における運動によるHR応答の弱まりの背後にあるメカニズムを調査する.
- 交感神経系の活動とベータアドレナゲン受容体の機能を決定する.
主な方法:
- 運動によるHRとノレピネフリン (NE) レベルを,心筋梗塞の患者59人と正常な被験者46人に比較した.
- イソプロテレノール注入に対するHR応答と,CHF患者におけるミルリノンの効果を評価した.
- ピーク運動酸素消費量 (VO2) と相関するHRとNE応答.
主要な成果:
- CHFの患者はピーク運動HRとHR増加が減少しており,ピークVO2と強く相関していました.
- ピーク運動のNEレベルとインクリメントは,CHF患者で弱まりませんでした.
- 運動HRとNEの増加の比率,シノアトリアル節の交感応答性の指標は,CHFで低下し,運動障害と逆に関連していました.
結論:
- CHFにおける運動に対する弱まったHR応答は,部分的には,ポストシナプスベータアドレナリン受容体の無感化によるものです.
- 交感神経系の活動は休息時に上昇しますが,CHFでは運動中にHRを十分に増加させません.
- ベータ・アドレナジック経路を標的とした薬理学的介入は,CHFにおける運動能力を改善する可能性がある.
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