Comparative effects of propranolol and practolol in the early stages of experimental canine myocardial infarction.

摘要: 1 The effects of propranolol and practolol, at equivalent myocardial beta-adrenoceptor blocking doses, (as assessed by the degree shift isoprenaline dose-response curves) were investigated in anaesthetized greyhounds before after acute coronary artery ligation. 2 When administered intravenously to intact close-chest dog, (0.1 mg/kg) practolol (0.5 caused similar decreases heart rate, left ventricular dP/dt max, blood flow cardiac output. Only increased peripheral vascular resistance. 3 2-3h ligation, significantly decreased both normally perfused ischaemic regions heart. There was also electrocardiographic evidence further deterioration propranolol; two out seven animals died following this treatment. 4 Practolol when ligation normal but area remained unchanged. Evidence obtained from electrocardiographic, temperature, O2 consumption lactate measurements that administration contrast propranolol, benefited myocardium. 5 Analysis results suggests beneficial action may be related least mechanisms. Firstly ability increase period during diastole perfusion subendocardium is possible, without decreasing transventricular pressure period. Secondly does not unmask alpha-adrenoceptor vasoconstriction region.