IV. THE ANTAGONISTIC ACTIONS OF EPINEPHRIN AND POTASSIUM CHLORIDE ON THE TONUS AND TONUS WAVES IN THE EXCISED TERRAPIN AURICLES

¹ From the Department of Physiology and Pharmacology and the Henry S. Denison, Research Laboratories in the University of Colorado

Potassium chloride causes an increase in the general tone and tonus waves and may cause a disappearance of the contractions in the excised terrapin auricles. The strength of potassium necessary to produce this change varies in different auricles but the average found for 55 experiments was 0.22 per cent.

The results with calcium chloride were so variable that no deductions could be drawn.

No antagonistic action but rather a synergistic action exists between potassium chloride and calcium chloride upon the general tone and tonus waves in the auricles of terrapin.

Epinephrin in proper doses causes a disappearance of the general tone and tonus waves aroused by potassium chloride alone or in combination with calcium chloride, causes a reappearance of the contractions if they have disappeared and increases the rate and the strength of contractions when still present.