Abstract
Using Chance-Hagihara's techniques, oxydative phosphorylation was studied on the heart muscle mitochondria isolated from guinea pigs pretreated with an intravenous injection of drugs. Sympathomimetics and adrenergic blocking agents systemically administered, produced a remarkable increase in QO2 at state 4 on oxidative phosphorylation in heart mitochondria. Although the value of respiratory control index showed a dose dependent lowering, ADP/0 ratio was not significantly lowered unless very large doses were given. Epinephrine and norepinephrine when added to the incubation medium, did not produce any direct effect on the respiratory function of isolated mitochondria. Thus, it was postulated that sympathomimetics induced some impairment on mitochondrial respiration by a systemic action.
