Inhibition of endo- and epicardial glycogenolysis by propranolol in ischemic hearts

Abstract

The effect of coronary artery ligation on myocardial glycogenolysis was studied in the endo- and epicardial layers of the left ventricle in dogs pretreated with saline or 1 mg/kg of propranolol. Coronary artery ligation was performed by ligating one of the small branches of the left anterior descending coronary artery. Even after coronary artery ligation, neither increase in phosphorylase activity nor breadkown of glycogen was observed in both layers of ischemic region of myocardium in propranolol-pretreated dogs. Pretreatment with propranolol appeared to inhibit the increase in glycogenolysis being caused by coronary artery ligation. Propranolol did not inhibit completely the coronary artery ligation-induced increase in glucose 6-phosphate and lactate and decrease in phosphocreatine in the myocardium, especially in the endocardial layers.