V. FURTHER STUDIES ON THE ANTAGONISTIC ACTION OF EPINEPHRIN TO CERTAIN DRUGS UPON THE TONUS AND TONUS WAVES IN THE TERRAPIN AURICLES

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

Nicotine in 0.1 to 1 per cent solution causes an increase in the general tonus and tonus waves. The height of the contractions may be either increased or decreased depending upon the increased general tone.

In small doses of 0.03 to 0.05 per cent solution there is no increase in general tonus or tonus waves but increased height of contractions.

Adrenalin chloride in strong solutions antagonizes the action of nicotine upon the terrapin auricles.

Digitalis in solutions, of from 0.3 to 0.5 per cent causes increased tonus and tonus waves which are antagonized by adrenalin chloride.

Barium chloride caused an increase in rate, general tonus and tonus waves in the terrapin auricles. Adrenalin chloride antagonizes the tonus waves but does not effect the general tonus to the same extent.