THE ACTION OF ADRENALINE AND OF CERTAIN DRUGS UPON THE ISOLATED CRUSTACEAN HEART

¹ Marine Biological Laboratory, Plymouth, and the Department of Physiology, University of Edinburgh

1. The action of adrenaline, ephedrine, ergotoxine, pilocarpine, and atropine has been studied on the heart of the crabs Maia squinado, Cancer pagurus, and Carcinus moenas.

2. A method for the perfusion of the isolated heart in these genera is described.

3. Adrenaline produces a marked acceleration of the rhythm and an increase in tone of the heart-muscle in all cases.

4. In Cancer, in addition to the above effects, there is a pronounced increase in the amplitude of the beats.

5. The action of adrenaline is not reversible. In the lowest dilution in which it gives any effect, that effect is excitatory.

6. Ephedrine has no action on the crab heart.

7. Ergotoxine has a depressant action, but does not antagonise or reverse the action of adrenaline.

8. Pilocarpine produces an effect similar to that obtained with adrenaline.

9. Atropine has by itself no action on the heart in the dilutions employed, but antagonises the effect of pilocarpine.

10. Atropine has no effect on the response to adrenaline.

The author's acknowledgments are due to Dr E. J. ALLEN and Mr C. F. A. PANTIN for placing the facilities of the Marine Biological Laboratory at his disposal, and to Miss B. B. SMITH for assistance in conducting the experiments.