Effects of Epinephrine, Norepinephrine and Isopropylarterenol on the Isolated Auricles of Four Mammalian Species

¹ From the Department of Pharmacology, Cornell University Medical College, New York City

Epinephrine, norepinephrine and Isuprel were tested on the amplitude of contraction and rate of the auricles of the rat, guinea pig, rabbit and cat. In all species Isuprel was much more potent in its effects than the other amines. In the rat auricle Isuprel dilutions of 1 part in 20 trillion produced marked changes in rate and amplitude. Norepinephrine was the least potent of the three amines. The right auricle was more sensitive than the left. The great potency of Isuprel suggests that even the small concentrations of it or a similar amine which Lockett (1) reported finding in the adrenal gland would produce marked changes in auricular function. Therefore, it may be physiologically important. The ability of dilute solutions of Isuprel to restore a rapid spontaneous beat to an asystolic auricle suggests a possible role in the management of cardiac arrest. The marked differences in species response to the three amines may make this a useful bioassay technique. The combination of rat and guinea pig auricles should distinguish between the three amines in dilute solutions.

Note:
with the technical assistance of Ann Kirk