Intestine in Reflex Chemical Control of Breathing

Abstract

In dogs anesthetized with Na Pentothal, occlusion of the artery and vein of intestinal loops completely isolated except for the extrinsic nerves, induced transient augmentation of breathing. Localized admn. of NaCN to the isolated loop either by application to the peritoneal surface or intravasc, during maintenance of the vascular occlusion, resulted in a small initial depression of breathing followed by a pronounced augmentation. These reversible effects were demonstrated to be of reflex origin by sectioning extrinsic nerves and are induced by chemical changes in the tissues resulting from diminished blood flow, chemical changes in the blood itself and by chemical changes in the intraperit. fluid acting on peritoneal surfaces. These respiratory reflexes serve to supplement other mechanisms of respiratory regulation.