THE EFFECTS OF ANALGESIC DRUGS UPON EXCISED FROG AND TERRAPIN HEARTS AND UPON THE TERRAPIN CARDIAC VAGUS NERVE

¹ Department of Pharmacology, Jefferson Medical College, Philadelphia, Pennsylvania

1. Racemates A and B of 1-amino-1-phthalidylpropane hydrochloride when applied to the perfused excised frog heart, decrease the rate and force of the cardiac contractions. These changes are similar to those seen in the intact mammalian heart upon intravenous injection of these compounds. The results with aminopyrine and antipyrine were variable.

2. Racemates A and B when applied to the exposed terrapin heart decrease the rate but not the height of the contractions.

3. Racemates A and B of 1-amino-1-phthalidylpropane hydrochloride, aminopyrine, acetanilid and antipyrine decrease the response of the heart to cardiac vagus nerve excitation. In high concentrations, racemates A and B and aminopyrine may cause complete block of the response of the heart to vagus nerve stimulation.

4. Racemate A of 1-amino-1-phthalidylpropane hydrochloride was found to be twice as toxic to the frog and turtle heart as was racemate B.

5. All of the analgesic drugs studied have a direct depressant action upon cardiac muscle.