Protecting Ischemic Myocardium,Minimizing Infarct Size,and Enhancing Myocardial Repair. Effect of Propranolol on Ischemic Myocardial Necrosis and the Local Distribution of Coronary Collateral Blood Flow.

摘要

Propranolol has been evaluated as a prototype agent capable of reducing infarct size following experimental myocardial ischemia in dogs. Necrosis has been quantitated from histologic sections in hearts of groups of dogs after 40minute of temporary coronary occlusion and after 24hours of permanent coronary ligation. In both models,propranolol therapy reduced infarct size. Additional experiments were done to evaluate potential mechanisms of protection. Results of dose-response studies and the ineffectiveness of d-propranolol suggest that protection is related to beta-blockade. Following propranolol administration,collateral flow 5minutes after occlusion was reduced. Despite decreased initial flow,less necrosis developed over a 24hour period. These results suggest that protection by beta-blockade is more likely related to prevention of direct effect of catecholamines on myocardial cells.