Effects of Bunazosin, a Selective α₁-Adrenergic Blocking Agent, on Myocardial Energy Metabolism in Ischemic Dog Heart

抄録

Effects of a selective α₁-adrenergic blocking agent, bunazosin, on myocardial energy metabolism in the ischemic heart were studied. Ischemia was induced by ligating the left anterior descending coronary artery of the dog heart. Bunazosin was injected intravenously either 5 or 20 min before coronary artery ligation. Hearts were removed 3 min after coronary ligation and used for determination of the levels of cardiac tissue metabolites. Ischemia decreased the levels of ATP, creatine phosphate, glycogen and glucose, and increased the levels of ADP, AMP, hexose monophosphates and lactate. The energy charge potential (ECP) calculated was decreased by ischemia. Pretreatment with bunazosin inhibited the decrease in ATP and the increase in AMP caused by ischemia, resulting in the high value of ECP in the ischemic myocardium. Bunazosin also prevented the changes in carbohydrate metabolism caused by ischemia. It is concluded that bunazosin may reduce the influence of ischemia on the myocardium.