ALINIDINE PREVENTS HYPOPERFUSION-INDUCED TRANSMURAL FLOW REDISTRIBUTION IN ISOLATED PACED RAT HEARTS

1. The effect of alinidine on transmural flow redistribution during hy poperfusion was studied in the isolated rat heart. 2. Low flow perfusi on of paced (5 Hz) rat Langendorff preparations with Tyrode's solution for 60 min resulted in loss of left ventricular pressure amplitude an d contracture. 3. In the presence of 45.6 mu mol/L alinidine in the hy poperfusion medium contractility was maintained and contracture was mi ssing. 4. Myocardial sphere densities were assessed by infusion of flu orescent microspheres after 60 min of hypoperfusion. Histomorphometric evaluation of the left ventricular wall indicated marked redistributi on of myocardial flow to the epicardium. Endo/epicardial quotients of sphere densities were significantly greater in alinidine-treated heart s. 5. Perfusion of hearts with 45.6 mu mol/L alinidine for 30 min at a pressure of 80 cmH(2)O decreased coronary flow and contractility, but did not change the transmural quotient of sphere densities. 6. These results show that in isolated rat hearts with a ventricular wall of on ly 3-4 mm thickness severe hypoperfusion induces a shift in transmural flow distribution which is prevented by alinidine.