Cardioprotective effect of metipranolol on ischemic heart muscle.

The effect of the beta-adrenoceptor antagonist metipranolol given twice daily in a dose of 0.5 mg/kg body weight for 3 days on respiration, respiratory control index of mitochondria and oxidative phosphorylation was measured in the heart muscle of anesthetized dogs after 60 min of induced ischemia. In control animals pretreated with saline, all measured variables with the exception of the coefficient of oxidative phosphorylation were significantly decreased. In contrast, pretreatment with metipranolol significantly improved all measured myocardial metabolic variables. The effect of metipranolol on the oxidative phosphorylating processes was more pronounced when the metabolic substrate was glutamate than when it was pyruvate.