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Endogenous endothelin maintains coronary artery tone by endothelin type A receptor stimulation in patients undergoing

Z S Kyriakides1, D T Kremastinos, E Bofilis

  • 12nd Department of Cardiology, Onassis Cardiac Surgery Center, Athens, Greece. zskyr@otenet.gr

Heart (British Cardiac Society)
|July 25, 2000
PubMed

Insights

Endogenously generated endothelin-1 (ET-1) stimulates endothelin type A (ET(A)) receptors, contributing to human coronary vascular tone. Blocking ET(A) receptors with BQ-123 increased coronary artery diameter and blood flow.

Area of Science:

  • Cardiovascular Physiology
  • Pharmacology
  • Endothelin Receptor Antagonism

Background:

  • Endothelin-1 (ET-1) is a potent vasoconstrictor peptide.
  • The role of endothelin type A (ET(A)) receptors in maintaining human coronary vascular tone is not fully understood.

Purpose of the Study:

  • To investigate the contribution of endothelin type A (ET(A)) receptor stimulation by endogenously generated endothelin-1 (ET-1) to the maintenance of coronary vascular tone in humans.

Main Methods:

  • A controlled clinical study involving 14 subjects (7 healthy, 7 with coronary artery disease).
  • Infusion of BQ-123, a selective ET(A) receptor antagonist, into the left coronary artery.
  • Measurement of coronary artery diameter and blood flow velocity using coronary arteriography and Doppler flow guidewire.

Main Results:

  • BQ-123 infusion significantly increased proximal (6%) and distal (12%) left anterior descending coronary artery diameter.
  • Coronary blood flow increased by 23% and coronary vascular resistance decreased by 28% post-BQ-123 infusion.
  • Patients with and without coronary artery disease showed similar responses to BQ-123.

Conclusions:

  • Endogenously produced ET-1, via ET(A) receptor stimulation, contributes to basal coronary artery tone in humans.
  • The specific role of endothelin type B (ET(B)) receptors in this process requires further investigation.
Abstract

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