Renal krypton-85 washout in hemorrhage in sinoaortic-denervated dogs

Two groups of dogs, prepared as (a) sham controls and (b) bilaterally carotidsinusectomized and bilaterally-vagotomized experimental animals, were subjected to hemorrhage to study the reflex control of kidney washout compartments. Krypton-85 disappearance curves after renal artery injections of ⁸⁵Kr in saline were obtained and analyzed before bleeding (control), after bleeding to 50 mm Hg blood pressure, and 2.5 hr after hemorrhage. Before hemorrhage, the experimental group exhibited a significantly greater mean blood pressure, component II flow, and total renal blood flow (RBF) than the control group. Although the component I flow rates were not significantly different, the percentage of radioactivity was smaller in the experimental dogs. Immediately after hemorrhage, both groups exhibited a marked tendency toward a single component in place of components I and II. Of primary interest is the fact that both groups of dogs exhibited similar flow components after hemorrhage. Both groups reverted back to three component curves by 2.5 hr after hemorrhage, but the control group had a much greater flow in component I. In addition, the control group took back a significantly larger volume of blood from the hemorrhage bottle. It appears that carotid sinus removal and vagal sectioning resulted in a significant degree of prehemorrhage and renal blood flow redistribution, but not complete redistribution as found in hemorrhagic hypotension. Factors other than the sympathetic nervous system may have been involved.