冠動脈微循環におけるアルファ1およびアルファ2アドレネルゲン受容体の機能的分布
1Department of Medical Physiology, Texas A&M University, College Station.
Circulation
|November 1, 1991
まとめ
冠動脈小動脈は,血管運動のトーンが無傷であるとき,アルファ-アドレナジック収縮を逃れ,しかし,hyperfusionの間に敏感になります. アルファ-1受容体は広く存在し,アルファ-2受容体は主に動脈小節に存在します.
科学分野:
- 心血管生理学 心血管の生理学
- アドレナゲン受容体の薬理学 アドレナゲン受容体の薬理学
背景:
- 冠動脈の微循環におけるアルファ1およびアルファ2アドレナリン受容体の分布と機能を調査することは,血流調節を理解するために重要である.
- 以前の研究では,洞察が提供されましたが,上心動脈冠動脈微血管の内部での詳細な機能的マッピングはまだ必要です.
研究 の 目的:
- エピカルディアの冠動脈微循環におけるアルファ1およびアルファ2アドレナリン受容体の機能的分布を決定する.
- 異なる生理学的条件下で,これらの受容体が冠動脈と動脈小節に与える異なる効果を解明する.
主な方法:
- 選択性アルファ1アドレナジックアゴニスト (フェニレフリン) とアルファ2アドレナジックアゴニスト (BHT-933) を鼓動する心臓モデルで冠動脈内投与する.
- 冠動脈マイクロ血管直径の測定は,無傷の血管運動のトーンと冠動脈低血流の条件下で行われます.
- 選択性アルファ1 (プラゾシン) とアルファ2アドレナゲン (SKF 104078) 反抗剤を使用したアゴニスト選択性の確認.
主要な成果:
- フェニルエフリンは小冠動脈 (血管>100ミクロン) の収縮を引き起こしたが,血管動脈 (<100ミクロン) の収縮は起こさなかった.
- ハイポパーフュージョンの間,フェニルエフリンは小動脈と小動脈管の両方を収縮させました.
- BHT-933はヒポパーフュージョン中に選択的かつ有意に動脈管を狭め,通常の条件では効果はありません.
結論:
- 冠動脈小動脈は,冠動脈とは異なり,血管運動のトーンが保たれていれば,アルファアドレナジック収縮から"自己調節的な脱出"を示します.
- ハイポパーフュージョンの間,アルファ1およびアルファ2アドレナージックアゴニストの両方が冠動脈小動脈を著しく収縮させます.
- アルファ2受容体は主に動脈小胞に位置しているように見えますが,アルファ1受容体は冠動脈微循環全体により広く分布しています.
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