Effects of disophenol on the isolated, perfused rat heart

Perfusion of hearts with disophenol caused significant alterations in spontaneous heart rate, coronary flow, isometric systolic tension, metabolite levels and electrical activity. Phosphorylase a levels were normal at 10 and 100 $\text{ng}\text{ml}$ but decreased significantly at 1000 $\text{ng}\text{ml}$. Disophenol markedly depressed spontaneous heart rate at 1000 $\text{ng}\text{ml}$ and similar decreases were noted in coronary flow and isometric systolic tension. Diastolic tension, however, increased greater than threefold after 60 min of perfusion at a level of 1000 $\text{ng}\text{ml}$. At this concentration, serious disturbances in electrical activity were also evident. Disophenol depleted tissue glycogen, adenosine-5'-triphosphate, total adenine nucleotides and creatine phosphate levels while it elevated lactate levels. No disophenol-induced lesions, gross or microscopic, were found.