VENTRICULAR RESPONSE IN CAFFEINE-NICOTINE ANTAGONISM

¹ From the Physiological Laboratory, Long Island University, Brooklyn, New York

1. Nicotine, in the concentrations employed, affects the ventricular muscle of the frog directly by producing an increased tonus and a decreased amplitude of the contraction.

2. Caffeine, in the concentrations employed, does not affect the tonus; and, in the percentages of 0.5 per cent caffeine-in-Ringer or below, it definitely increases the amplitude of the ventricular strip contraction in the frog.

3. Complete recovery of the normal ventricular strip behavior occurs regularly after treatment by either 0.2 per cent caffeine-in-Ringer, or 0.2 per cent nicotine-in-Ringer.

4. Definite antagonism occurs between caffeine and nicotine in their separate physiological effects upon the ventricular muscle of the frog. Under the conditions of the experimental series reported here, the neutralization proportionality for 0.2 per cent RN vs. 0.2 per cent RC was 15 cc. RN:85 per cent RC.