Effect of endothelin receptor antagonists on ventricular susceptibility in postinfarcted rats

Am J Physiol Heart Circ Physiol. 2008 Apr;294(4):H1871-9. doi: 10.1152/ajpheart.01129.2007. Epub 2008 Feb 15.

Abstract

This study investigated whether selective endothelin (ET) type A (ET(A)) or nonselective ET(A)/ET(B) receptor blockade exerted antiarrhythmic effects through attenuated sympathetic reinnervation after infarction. Twenty-four hours after ligation of the left anterior descending artery, male Wistar rats received either vehicle, ABT-627 (selective ET(A) receptor antagonist), bosentan (nonselective ET(A)/ET(B) receptor antagonist), or hydralazine for 4 wk. The measurement of myocardial ET-1 levels at the remote zone revealed a significant increase in vehicle-treated infarcted rats compared with sham-operated rats, consistent with increased activities of ET-1 after infarction. Sympathetic nerve function changes assessed by the norepinephrine content of myocardium and the dialysate and plasma dihydroxyphenylglycol levels were parallel to ET-1 levels. Immunohistochemical analysis for tyrosine hydroxylase, growth-associated protein 43, and neurofilament also confirmed the change of nerve function. This was accompanied with a significant upregulation of nerve growth factor protein expression and mRNA in the vehicle-treated infarcted rats, which reduced after the administration of either ET(A) or ET(A)/ET(B) blockade to a similar extent. The beneficial effects of ET receptor antagonists on sympathetic nerve function and structures were dissociated from their blood pressure-lowering effect because ET receptor antagonists and hydralazine reduced arterial pressure similarly. Arrhythmic severity during programmed stimulation in ET receptor antagonists-treated rats was significantly lower than that in vehicle-treated infarcted rats. Our data indicate that the ET system, especially via ET(A) receptors, plays an important role in attenuating sympathetic reinnervation after infarction. Independent of their hemodynamic effects, a chronic use of either ET(A) or ET(A)/ET(B) antagonists may modify the arrhythmogenic response to programmed electrical stimulation.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Anti-Arrhythmia Agents / pharmacology*
  • Anti-Arrhythmia Agents / therapeutic use
  • Antihypertensive Agents / pharmacology
  • Arrhythmias, Cardiac / etiology
  • Arrhythmias, Cardiac / metabolism
  • Arrhythmias, Cardiac / physiopathology
  • Arrhythmias, Cardiac / prevention & control*
  • Atrasentan
  • Blotting, Western
  • Bosentan
  • Cardiac Pacing, Artificial
  • Disease Models, Animal
  • Endothelin A Receptor Antagonists*
  • Endothelin B Receptor Antagonists*
  • Endothelin-1 / metabolism
  • GAP-43 Protein / metabolism
  • Hemodynamics / drug effects
  • Hydralazine / pharmacology
  • Immunohistochemistry
  • Male
  • Methoxyhydroxyphenylglycol / analogs & derivatives
  • Methoxyhydroxyphenylglycol / blood
  • Myocardial Infarction / complications
  • Myocardial Infarction / drug therapy*
  • Myocardial Infarction / metabolism
  • Myocardial Infarction / physiopathology
  • Myocardium / metabolism*
  • Nerve Growth Factor / genetics
  • Nerve Growth Factor / metabolism
  • Neurofilament Proteins / metabolism
  • Norepinephrine / metabolism
  • Polymerase Chain Reaction
  • Pyrrolidines / pharmacology*
  • Pyrrolidines / therapeutic use
  • RNA, Messenger / metabolism
  • Rats
  • Rats, Wistar
  • Receptor, Endothelin A / metabolism
  • Receptor, Endothelin B / metabolism
  • Sulfonamides / pharmacology*
  • Sulfonamides / therapeutic use
  • Sympathetic Nervous System / drug effects*
  • Sympathetic Nervous System / enzymology
  • Sympathetic Nervous System / metabolism
  • Sympathetic Nervous System / physiopathology
  • Time Factors
  • Tyrosine 3-Monooxygenase / metabolism
  • Up-Regulation

Substances

  • Anti-Arrhythmia Agents
  • Antihypertensive Agents
  • Endothelin A Receptor Antagonists
  • Endothelin B Receptor Antagonists
  • Endothelin-1
  • GAP-43 Protein
  • Neurofilament Proteins
  • Pyrrolidines
  • RNA, Messenger
  • Receptor, Endothelin A
  • Receptor, Endothelin B
  • Sulfonamides
  • Hydralazine
  • Methoxyhydroxyphenylglycol
  • Nerve Growth Factor
  • Tyrosine 3-Monooxygenase
  • Bosentan
  • 3,4-dihydroxyphenylglycol
  • Atrasentan
  • Norepinephrine