Water and Electrolytes in Congestive Failure 287 



concentration of oxygen), CO rose in a similar way to the rise 

 observed in hypoxaemic hypoxia in intact animals, 

 (d) Harrison and co-workers (1927) concluded from their 

 studies on experimental hypoxaemia in dogs that the oxygen 

 tension in the myocardium is the most important factor 

 determining the rise in CO. 



A direct efferent nervous influence on the kidneys was 

 demonstrated by Kaplan and Rapoport (1951) and Blake 

 (1952) in dogs with unilateral renal denervation. Tubular 

 reabsorption of sodium was less in the denervated kidney. 

 Bykov and Alexejev-Berkmann (1930, 1931) (see Bykov, 

 1952) found that a conditioned "water" diuresis in dogs may 

 be partly inhibited by denervation of the kidneys. 



Renal blood flow was measured only in the experiments of 

 Kaplan and Rapoport (1951), where the increased renal 

 excretion of water and electrolytes after splanchnicotomy was 

 independent of changes in renal blood flow. Our experimental 

 results in patients with heart failure (see above) demonstrated 

 a close relationship between changes in renal blood flow and 

 tubular reabsorption of water and electrolytes. 



A partial answer to this question can be found in the experi- 

 ments of Cort and Kleinzeller (1956) on isolated kidney 

 tissues of rabbits. Changes in transport of cations and water 

 were studied during two hours' exposure of kidney slices to 

 unoxygenated physiological saline at 0°, and then after 10 

 and 30 minutes of incubation in Krebs' phosphate saline with 

 oxygen at 25°. One kidney was decapsulated and denervated 

 14 days before the actual experiment. It was shown that there 

 was a greater influx of sodium into the denervated slices 

 during leaching at 0°, and a slowcjr expulsion of sodium from 

 the denervated kidney slices during the incubation period. 

 The changes in water content of the slices were in the same 

 direction as the shifts of sodium. The difl'erence between 

 denervated and innervated kidney was, however, not marked. 

 Potassium loss during the two-hour leaching period was 

 greater, and its reaccumulation during subsequent incubation 

 slower, in the denervated kidney. 



