在横跨左心室壁的冠状动脉小动脉中异质β2-上腺受体表达和扩张
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
概括
贝塔腺素受体激动剂导致冠状动脉流量重新分配. 这项研究发现,贝塔2-上腺受体在心下动脉小动脉中表达更高,通过对ATP敏感的通道导致更大的血管扩张.
科学领域:
- 心血管生理学心血管生理学
- 微循环研究 微循环研究
- 上腺体信号传递
背景情况:
- 之前的研究表明,β-腺受体激动剂会改变冠状动脉流量分布.
- 这种流量再分配的确切机制,特别是在左心室壁,仍然不清楚.
- 假设β-腺受体及其对心室壁的反应具有异质分布.
研究的目的:
- 调查异质β-上腺受体在冠状动脉微循环中的分布和功能的假设.
- 确定β-受体和通道在冠状动脉小动脉血管扩张中的作用.
- 为了比较心下和心下动脉小动脉对β-腺受体激活剂的反应.
主要方法:
- 在体外血管扩张研究中,孤立的猪心下和心下动脉小动脉 (<100微米) 被加压.
- 评估了对非选择性 (异二醇) 和选择性 (益二醇) β-腺受体激动剂的反应.
- 评估了β-上腺受体抑制剂 (ICI-118,551,阿提诺洛尔) 和K(ATP) 通道调节剂 (glibenclamide,pinacidil) 的作用.
- 使用RT-PCR和免疫组织化学量化β-腺受体表达 (mRNA和蛋白质).
主要成果:
- 副心血管和副内心血管都扩大到异二醇和益二醇,但副心血管显示出更高的灵敏度和扩张能力.
- 异二醇诱导的血管扩张是由ATP敏感 (K(ATP)) 通道介导的,主要涉及β2-腺受体.
- 与心下动脉小管相比,心下动脉小管表现出明显更高的β2-上腺受体mRNA和蛋白质表达.
结论:
- 选择性β2-上腺受体激活通过打开K ((ATP)) 通道,导致心下和心下动脉小动脉的血管扩张.
- 在心下动脉小管中增强的血管扩张归因于它们更高的β2-上腺受体表达.
- 这些发现阐明了β-上腺受体介导的冠状动脉流量再分配的机制.
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