Nonselective ETA/ETB-receptor blockade increases systemic blood pressure of Bio 14.6 cardiomyopathic hamsters

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Jean-Claude Honoré1, Emilie Carrier, Marie-Hélène Fecteau

  • 1Department of Pharmacology, Faculty of Medicine and Health Sciences, Universite de Sherbrooke, 3001 12th Avenue North, Sherbrooke, QC J1H5N4, Canada.

Canadian Journal of Physiology and Pharmacology
|June 3, 2008
PubMed

Insights

Selective endothelin ETB receptor antagonists increase blood pressure and cardiac weight in heart failure models. Blocking ETA receptors may offer cardiac benefits by reducing endothelin levels.

Area of Science:

  • Cardiovascular Research
  • Pharmacology
  • Heart Failure Pathophysiology

Background:

  • Congestive heart failure (CHF) involves complex signaling pathways, including the endothelin system.
  • Endothelin receptors ETA and ETB play critical roles in cardiovascular regulation and disease progression.

Purpose of the Study:

  • To investigate the specific roles of endothelin ETA and ETB receptors in cardiomyopathy-induced congestive heart failure.
  • To evaluate the effects of selective ETA- and ETB-receptor antagonists on cardiac function and systemic hemodynamics.

Main Methods:

  • Chronic treatment with selective ETA-receptor antagonist (atrasentan) and ETB-receptor antagonist (A-192621) in Bio 14.6 cardiomyopathic hamsters.
  • Assessment of functional parameters (mean arterial pressure, left ventricular end-diastolic pressure) and biochemical markers (plasma endothelin levels, left ventricle:body weight ratio).

Main Results:

  • Selective ETB-receptor antagonism and combined ETA/ETB antagonism increased systemic blood pressure.
  • Selective ETB-receptor blockade significantly elevated plasma endothelin levels, further amplified by ETA-receptor antagonism.
  • Treatment with A-192621 (alone or combined) increased the left ventricle:body weight ratio.
  • Selective ETA-receptor antagonism decreased left ventricular end-diastolic pressure and reduced left ventricular endothelin levels.

Conclusions:

  • ETB receptors are crucial for limiting circulating endothelin levels in heart failure.
  • Selective ETA-receptor antagonists may offer improved cardiac benefits in CHF due to their effect on endothelin levels.

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