Effects of catecholamines on myocardial energy metabolism as studied by an organ redoximeter

With the use of an organ redoximeter, the effects of noradrenaline, adrenaline, isoproterenol, and phenylephrine on the oxidation-reduction state of the myocardial pyridine nucleotides were studied in the canine heart-lung preparation supported by a donor. Noradrenaline and adrenaline produced an initial, transient improvement, and phenylephrine a sustained improvement, of the redox state, while isoproterenol produced a depression. Pretreatment of the preparation with adrenergic alpha-blockers resulted in an abolishment of the improvement by noradrenaline, adrenaline, and phenylephrine, while the depression by isoproterenol remained unchanged. Whereas noradrenaline and adrenaline produced a sustained improvement after an adrenergic beta-blocker, propranolol, the effect of isoproterenol was abolished. These findings suggest that sympathomimetic amines can produce an improvement of the myocardial energy metabolism through activation of the adrenergic alpha-receptor. The depression of the myocardial oxidation-reduction state was taken to represent an acceleration of glycolysis.