STUDIES ON THE PHARMACOLOGY OF SODIUM CITRATE I. THE INFLUENCE OF SODIUM CITRATE ON RESPIRATION AND CIRCULATION

¹ From the Department of Physiology and Pharmacology of the University of Georgia, Augusta, Georgia

1. Small and medium doses of sodium citrate stimulated respiration in dogs, cats and rabbits under urethane anesthesia.

2. Such doses may cause stimulation or depression of respiration in dogs anesthetized with chloretone.

3. Small and medium doses given to dogs, when morphineether narcosis was employed, were without any effect on respiration in some experiments, while in others the action was the same as under chloretone anesthesia.

4. Respiration was depressed or paralyzed by large doses of citrate even when injected slowly into the circulation, and by medium doses when repeated at short intervals.

5. Transitory acceleration of respiration occurred when large doses of citrate were injected intramuscularly in unanesthetized animals; also when injected subcutaneously into decerebrated and into unanesthetized animals.

6. Respiration was only slightly accelerated or was slowed by citrate given after double vagotomy.

7. Small and medium doses of citrate were without effect or produced only a slight fall of blood pressure in dogs under chloretone or urethane anesthesia. A fall or a rise of blood pressure may occur when citrate is given to dogs under morphine-ether narcosis.

8. Small and medium doses of citrate given intravenously to cats under urethane anesthesia produced a fall of blood pressure of 30 to 60 per cent.

9. The fall of blood pressure in rabbits after small and medium doses of citrate was not pronounced, but was considerably increased when the dose was repeated a number of times or when a single large dose was given.

10. After intramuscular injection of large doses of citrate the fall of blood pressure was gradual.

11. The isolated heart of the frog and the turtle was depressed by the perfusion with low concentrations of sodium citrate. The turtle heart was much more resistant to the action of citrate than the frog heart.

12. The mammalian heart in situ was depressed by small and medium doses of citrate even after the vagus endings were paralyzed by atropine.

13. Stimulation of the cardio-inhibitory center in the medulla occurred after small and medium doses of citrate, and depression after large doses.