EFFECTS OF MORPHINE AND MEPERIDINE ON THE CENTRAL RESPIRATORY MECHANISMS IN THE CAT; THE ACTION OF LEVALLORPHAN IN ANTAGONIZING THESE EFFECTS

¹ Departments of Anesthesiology and Pharmacology, College of Physicians and Surgeons, Columbia University, and The Anesthesiology Service, The Presbyterian Hospital, New York, N.Y.

The effects of maorphine and of meperidine on the respiratory movements and on the various components of thue central respiratory mechanisms were studied in vagotomized,decerebrate cats. The antagonistic action of levallorphan was also examined.

Morphine and meperidine depress the responsiveness of the medullary respiratory centers to electrical stimulation, but at the dose levels studied they did not seem to impair the recruiting mechanism.

The pontile apneustic center is also depressed by these drugs.

Morphine and meperidine appear to have a preponderantly depressant action on respiratory rhythmicity. The facilitatory functon of the pontile pneumotaxic center and of the vagal afferents was reduced on absolished. The inhibitory vagal reflex was accentuated.

Levallorphan, as an amutagonist, has its main action in restoring the respiratory rhythmicity.