The effects of labetalol on MBF, IS and left ventricular function during coronary occlusion in the rabbits
- VernacularTitle:柳胺苄心定对急性心肌梗塞家兔心肌血流量梗死范围及左室功能的影响
- Author:
Duanxiang LI
- Publication Type:Journal Article
- Keywords:
Myocardial infarction;
Myocardium;
Rabbits
- From:
Chinese Journal of Pathophysiology
1986;0(03):-
- CountryChina
- Language:Chinese
-
Abstract:
The effects of labetalol (Lab), an alpha_1 and beta adrenoceptor blocking agent, and propranolol on myocardial blood flow (MBF), infarct size (IS) and left ventricular function during coronary occlusion in the rabbits were studied. After left ventricle coronary artery was ligated, the 53 rabbits were divided into 4 groups: control, propranolol 0.5mg/kg, Lab 1mg/kg and Lab 5mg/kg. After 30 min coronary occlusion, regional blood flow was determined by radioactive biological microspheres technique. After 5 hours occlusion, left ventricular pressure and its differentiation were measured and IS was estimated with NBT staining method. The results show: Lab 1mg/kg demonstrated mainly beta adrenoceptor blockade. It slowed heart rate, diminished myocardial oxygen consumption, decreased MBF except for infarct zone and reduced IS, the effects were similar to propranolol. Furthermore, it improved left ventricular function while propranolol did not. Lab 5mg/kg blocked alpha_1 and beta receptor simultanously. It decreased arterial blood pressure and heart rate, increased blood flow of myocardium and kidney relatively, diminished myocardial oxygen requrement more markedly than propranolol and reduced IS. These imply that simultanous alpha_1 and beta blockade have some advantage over beta blockade alone in the treatment of acute myocardial infarction.
