左心室壁の冠動脈小動脈の異質なβ2-アドレノ受容体発現と膨張は,左心室壁の横にある冠動脈小動脈にある
Travis W Hein1, Cuihua Zhang, Wei Wang
1Department of Medical Physiology, Cardiovascular Research Institute, College of Medicine, The Texas A&M University System Health Science Center, 702 Southwest H.K. Dodgen Loop, Temple, TX 76504. LKUO@tamu.edu.
Circulation
|July 14, 2004
まとめ
ベータ・アドレノ受容体アゴニストは冠動脈の流れの再分配を引き起こします. この研究では,心下動脈小動脈でβ2-アドレノ受容体の発現が高く,ATPに敏感なカリウムチャネル経由で血管拡張が大きくなる.
科学分野:
- 心血管生理学 心血管の生理学
- マイクロ循環研究 マイクロ循環研究
- アドレナジックシグナル伝達
背景:
- 以前の研究では,β-アドレノ受容体アゴニストが冠動脈の流れ分布を変化させることを示唆しています.
- このフロー再分配の正確なメカニズム,特に左心室壁におけるメカニズムは不明である.
- ベータ・アドレノ受容体と,その反応が心室壁全体に異質的に分布すると仮定された.
研究 の 目的:
- 冠動脈微循環における異質なβ-アドレノ受容体の分布と機能の仮説を調査する.
- 冠動脈動脈管の血管拡張におけるβ-アドレノ受容体とカリウムチャネルの役割を決定する.
- ベータ・アドレノ受容体アゴニストに対するサブピカールとサブエンドカルディアル動脈の反応を比較する.
主な方法:
- 豚のサブピカードおよびサブエンドカーディアル動脈 (<100ミクロン) の単離は,in vitro血管拡張試験において圧縮された.
- 非選択的 (イソプロテレノール) および選択的 (プロキャテロール) ベータ・アドレノ受容体アゴニストに対する反応が評価されました.
- ベータアドレノ受容体阻害剤 (ICI-118,551,アテノロール) とK ((ATP) チャンネル調節剤 (グリベンクラミド,ピナシジル) の効果が評価されました.
- ベータ・アドレノ受容体発現 (mRNAとタンパク質) は,RT-PCRと免疫ヒストロケミストリーを用いて定量化されました.
主要な成果:
- 胸下動脈と心臓下動脈の両方の動脈は,イソプロテレノールとプロカテロールに膨張したが,胸下動脈の血管は,より高い感度と膨張能力を示した.
- イソプロテレノールによって誘発された血管拡張は,ATPに敏感なカリウム (K ((ATP)) 経路によって媒介され,主にβ2-アドレノ受容体が関与しました.
- サベピカルディアアルテリオールは,ベータ2-アドレノ受容体のmRNAとタンパク質発現が,サブエンドカルディアアルテリオールと比較して,著しく増加した.
結論:
- 選択的なβ2-アドレノ受容体の活性化は,K (((ATP)) チャンネルを開くことで,心下動脈と心下動脈の両方の血管拡張を引き起こします.
- 胸下動脈小動脈における血管拡張の強化は,β2-アドレノ受容体のより高い発現に起因する.
- これらの発見は,β-アドレノ受容体媒介の冠動脈の流れ再分配のメカニズムを明らかにします.
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