THE ACTION OF SOME ENZYME INHIBITORS ON THE ISOLATED RABBIT AURICLE

¹ Department of Pharmacology, State University of New York, Upstate Medical Center, Syracuse, N. Y.

The effect of a number of procedures which reduce the energy supply have been tested on the various properties of auricular muscle. It could be shown that in most instances contractility and the spontaneous rate were depressed more than electrical excitability, conduction velocity or the effective refractory period. This is in marked contrast to the effects of quinidine where the refractory period, excitability and conduction velocity were more sensitive to this drug than either spontaneous rate or contractility.

The effects of inhibition of anaerobic glycolysis on auricular muscle was studied and it is concluded that this pathway does suppy some energy for both contractility and the spontaneous rate. The effects of a number of substrates on fluoroacetate inhibition have been determined. In the concentrations studied, dinitrophenol, although having marked effects on contractility, had little effect on spontaneous rate and the electrical properties of auricular muscle.