Ineffectiveness of nitroglycerin as an antiadrenergic agent on the cat heart.

The possibility that nitroglycerin modifies the metabolic effects of the sympathominietic amines wits tested in cats. Changes in the heart rate, blood pressure, height of the electrocardiographic T-wave and myoctirdial oxygen consumption following the injection of epinephrine or 1-arterenol were compared with changes in these indices after nitroglycerin was given with these sympathomimetic amines. The conclusion is reached that nitroglycerin does not significantly influence the effects of epinuphrine or 1-arterenol on the heart rate, the height of the electrocardiographic Twave or myocardial oxygen consumption. There is no evidence in these experiments to support the concept that nitroglycerin metabolicallv neutralizes the myocardial anoxating properties of the sympathomimetic amines.