Frederick M. Allen 



the recent resumption of this work a still simpler method has been introduced 

 by the use of either clamps or rubber ligatures applied outside the skin. The 

 results, presented in a paper before the American Society for Experimental 

 Pathology in April, 1941, are divisible into acute and chronic hypertension. 



Table 2 illustrates the results when the pedicles of explanted kidneys are 

 clamped or ligated by this method. There is an elevation of blood pressure, 

 rising sharply to a maximum, holding a plateau for a variable time, and in 

 the course of several hours declining slowly but not to normal. Whenever the 

 clamp or ligature is removed during this time, the pressure falls rapidly, so 

 that in the course of ten to twenty minutes it is found near or frequently be- 



TABLE 2 

 Male Dog, ii kg. Acute Hypertension with Clamping of Pedicles of 

 Explanted Kidneys, for 35 Minutes. 



low the original level. There are reasons for regarding this hypertension as 

 nervotis in character, apparently comprising both psychic and reflex compo- 

 nents. The slow^ decline of pressure during prolonged clampings is attributed 

 to nervous paralysis. The sharp fall when the clamps are remo\ed evidently 

 represents cessation of the nervous stimulus. 



This form of acute hypertension is interesting for several reasons. It may be 

 regarded as the result of an artificial spasm in the renal circulation, although 

 specificity is lacking, as explained below. It is also a hypertension occurring 

 in the absence of any possible substance derived from the kidneys. Further- 

 more, the results are precisely opposite to those obtained under special con- 

 ditions by Taquini" and Prinzmetal.'' They are not necessarily contradictory, 

 because the fact of humoral hypertension, in particular the production of a 

 hypertens've substance in the totally asphyxiated kidney, has been established 

 in carefully controlled experiments. The question whether this substance is 

 identical with that which is produced in partial renal asphyxia of the Gold- 

 blatt type, or whether it can rank as anything more than a post-mortem prod- 

 uct, still remains open. The humoral factor is demonstrated in "pure" experi- 

 ments in which, by anesthesia or otherwise, nervous and other interfering 

 factors are excluded as completely as possible. The experiments with explanted 

 kidneys are important as showing the behavior of the intact animal. In this 

 intact state there is no humoral hypertension following total renal asphyxia. 



