THE EFFECT OF VAGOTOMY AND DENERVATION OF THE CAROTID SINUS ON DIURESIS FOLLOWING PLASMA VOLUME EXPANSION

Abstract

The hypothesis exists that afferent vagal fibers, arising in cardiac atrial stretch receptors, serve as the sensory limb of a reflex mechanism sensitive to variations in blood volume and producing corresponding changes in urine flow. Section of the vagi did not, however, prevent the diuretic and chloruretic response to expansion of the plasma volume with isotonic infusions. Carotid sinus denervation alone or combined with vagotomy also failed to prevent the diuresis and chloruresis following infusion in most experiments, although in a few cases the response was absent or diminished after the combined procedure. Reasons are given for believing that the bovine albumin infusion used did not act directly on the kidney to increase urine output, but rather through a reflex mechanism which could not have depended on the integrity of the vagi. It is concluded that receptors additional to those in the cardiac atria and the carotid sinus must contribute to the sensory component of a reflex mechanism regulating plasma volume.