Selective beta 1 and beta 2 adrenoceptor blockade on epinephrine-induced arrhythmias in halothane anaesthetized dogs

Can J Anaesth. 1992 Oct;39(8):873-6. doi: 10.1007/BF03008299.

Abstract

Beta 2 as well as beta 1 adrenoceptors have been recognized in the heart of vertebrates. They mediate a positive chronotropic action of catecholamines. We compared the effect of selective beta 1 and beta 2 adrenoceptor antagonists on the genesis of halothane-epinephrine arrhythmias in dogs. The arrhythmogenic dose (AD) of epinephrine was increased in the presence of l-metoprolol, a selective beta 1 antagonist (8.40 +/- 1.13 micrograms.kg-1 x min-1; mean +/- SEM), compared with control value (2.62 +/- 0.56) (P < 0.05). In contrast, ICI-118,551, a selective beta 2 antagonist, did not change the AD (2.36 +/- 0.43). Adding ICI-118,551 to l-metoprolol did not affect the AD of epinephrine in the presence of l-metoprolol alone (6.34 +/- 0.74 vs 8.40 +/- 1.13). These results suggest that selective beta 1 blockade is effective in preventing halothane-epinephrine arrhythmias, but selective beta 2 blockade is not.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adrenergic beta-Antagonists / pharmacology*
  • Animals
  • Arrhythmias, Cardiac / chemically induced*
  • Arrhythmias, Cardiac / physiopathology
  • Arrhythmias, Cardiac / prevention & control
  • Blood Pressure / drug effects
  • Cardiac Complexes, Premature / chemically induced
  • Cardiac Complexes, Premature / physiopathology
  • Cardiac Complexes, Premature / prevention & control
  • Dogs
  • Dose-Response Relationship, Drug
  • Epinephrine / administration & dosage
  • Epinephrine / adverse effects*
  • Female
  • Halothane / administration & dosage
  • Halothane / adverse effects*
  • Heart Rate / drug effects
  • Male
  • Metoprolol / administration & dosage
  • Metoprolol / pharmacology*
  • Propanolamines / administration & dosage
  • Propanolamines / pharmacology*

Substances

  • Adrenergic beta-Antagonists
  • Propanolamines
  • ICI 118551
  • Metoprolol
  • Halothane
  • Epinephrine