The purely chronotropic effects of relaxin in the rat isolated heart

J Pharm Pharmacol. 1993 Oct;45(10):927-8. doi: 10.1111/j.2042-7158.1993.tb05625.x.


The endogenously occurring protein relaxin was evaluated for its cardiac effects in the rat isolated heart. Relaxin caused a dose-dependent tachycardia without positive inotropic effects in intact preparations and in preparations where the atria had been removed. It is concluded that relaxin acts on both the atrial and ventricular pacemakers to increase heart rate, but the precise mechanism of action remains unknown.

MeSH terms

  • Animals
  • Epinephrine / pharmacology
  • Heart Atria / drug effects
  • Heart Rate / drug effects*
  • Heart Ventricles / drug effects
  • In Vitro Techniques
  • Male
  • Rats
  • Rats, Sprague-Dawley
  • Relaxin / pharmacology*


  • Relaxin
  • Epinephrine