ISOLATION OF THE CAROTID SINUS PRESSORECEPTIVE RESPIRATORY REFLEX

Abstract

The carotid gland of anesthetized dogs was embolized; the aortic pressure was controlled and isolated carotid sinus perfused with aortic blood from the animal; pulmonary ventilation was controlled during open pneumothorax, connected to the exterior of a body-plethysmograph for recording breathing movements; the vago-sympathetic-aortic nerves were cut. The relation between endosinual pressure (mm. Hg.). and respiratory influence was inhibition of sigmoid progression, with threshold pressure at 20-24, max. pressure at 245 [plus or minus], and the greatest slope and turning point at 122-125 (avgs.). The influence persisted indefinitely, and when given time to develop amounted to a. maximal 70% decrease in breathing movements by one sinus. Comparison of these results with those of preliminary expts. without gland embolization indicated a capacity of the gland for intense respiratory stimulation due to self-excitation by its own metabolism during circulatory stasis.