Effects of adenosine on mechanical performance and electrical activity in the canine heart

Academic Article


  • The effects of adenosine on electrophysiological and mechanical properties of myocardium were studied in 26 canine right ventricular trabeculae. Increasing concentrations of adenosine (1, 10 and 100 μg/ml) exert a progressively greater negative (and only negative) inotropic effect. Neither the duration of the relaxation was affected by adenosine. However, in muscles undergoing inotropic stimulation with norepinephrine, adenosine significantly slowed the speed of contraction by prolonging the time-dependent parameters but had no significant effect on peak force and maximum extent of shortening. In ventricular trabeculae not exposed to norepinephrine, adenosine had no significant effect on resting potential but it significantly decreased the action potential upstroke velocity. Adenosine had little or no effect on the overshoot but it significantly abbreviated the plateau phase. Both of these effects observed in action potentials could serve to enhance local electrical stability. The site of action of adenosine appears to be primarily at the cellular membrane where it may interfere with both the fast and the slow inward current. An intracellular site of action is also possible since adenosine, which readily passes cellular membrane, interferes with the speed but not with the strength of contraction when trabeculae undergo inotropic stimulation with norepinephrine. A combination of suppression of contractility and preservation of electrical stability could therefore serve as important cardioprotective action by adenosine in ischemic myocardial cells.
  • Author List

  • Urthaler F; Woods WT; James TN; Walker AA
  • Start Page

  • 254
  • End Page

  • 260
  • Volume

  • 216
  • Issue

  • 2