Effects of isosorbide-5-mononitrate and isosorbide-2-mononitrate on the contractile and electrical activity and on the content of cyclic nucleotides in isolated heart muscles of the guinea-pig and dog

J Pharm Pharmacol. 1992 Aug;44(8):663-6. doi: 10.1111/j.2042-7158.1992.tb05490.x.

Abstract

Isosorbide-5-mononitrate and isosorbide-2-mononitrate, the metabolites of isosorbide dinitrate, were studied for their effects on the contractile and electrical activity and on the content of cyclic nucleotides in isolated heart muscles of guinea-pig and dog. Isosorbide-5-mononitrate at all concentrations tested and isosorbide-2-mononitrate at low concentrations did not produce significant changes in the mechanical activity of guinea-pig heart preparations. Isosorbide-2-mononitrate in concentrations above 10(-4) M inhibited the contractility and shortened the action potential of guinea-pig and dog heart muscle. Neither mononitrate had an effect on cAMP concentration but both induced a significant elevation of cGMP content in guinea-pig heart tissue, the effect of isosorbide-2-mononitrate being greater.

MeSH terms

  • Animals
  • Cyclic AMP / analysis*
  • Cyclic GMP / analysis*
  • Dogs
  • Guinea Pigs
  • Heart / drug effects*
  • Heart / physiology
  • In Vitro Techniques
  • Isosorbide Dinitrate / analogs & derivatives*
  • Isosorbide Dinitrate / pharmacology
  • Myocardial Contraction / drug effects*
  • Vasodilator Agents / pharmacology*

Substances

  • Vasodilator Agents
  • isosorbide-2-mononitrate
  • Cyclic AMP
  • Cyclic GMP
  • Isosorbide Dinitrate
  • isosorbide-5-mononitrate