Antiischemic effects of alinidine in paced isolated rat hearts.

Low-flow perfusion of paced (5 Hz) rat heart Langendorff preparation with Tyrode solution for 60 min caused a reduction or disappearance of left ventricular pressure amplitude. After 60 min of low-flow perfusion myocardial concentrations of high energy phosphates, as well as the energy charged potential, were diminished while lactate accumulated. Infusion of alinidine into the perfusate at low-flow conditions, resulted in a mean concentration of 15.0 +/- 0.60 microM, and prevented the mechanical and biochemical changes of low-flow perfusion, thus indicating maintenance of aerobic metabolism under hypoxic conditions. These heart rate-independent cardioprotective effects of the "specific bradycardic" drug alinidine are discussed in light of the adenosine antagonistic actions of this compound which should prevent coronary steal.