Effects of Epinephrine, Arterenol and Isuprel on the Electrical Potentials of Mammalian Heart Muscle: Inability of Nitrites to Block Effects

Abstract

Epinephrine, arterenol and isuprel tested on isolated cat papillary muscles produced elevation of the T deflection, widening of the R-T interval, and a U wave, in addition to the increased contractile force and automaticity previously described. Prior administration of nitroglycerin 1:100,000 or Na nitrite 1:10,000 did not alter the actions of the amines. Therefore, the effect of nitrites in angina is probably not due to an interference with the actions of the sympathomimetic amines on heart muscle. The actions of the drugs are classified into primary, secondary and tertiary groups to illustrate the complexity involved in interpreting the effects of drugs on heart muscle.