Section IV, 1917 [129] Trans. R.S.C. 



On the Nature of the Blood-pressure Curve produced by stimulation 

 of the Peripheral end of the Splanchnic Nerve. 



By J. P. Parsons and Swale Vincent. 



(t^rom the Physiological Laboratory, University of Manitoba, 



Winnipeg). 



(Read May Meeting, 1917.) 



It has been known for a long time that the rise of blood-pressure 

 brought about by stimulation of the peripheral end of the splanchnic 

 nerve is not simple. The curve obtained suggests at once that there 

 is more than one factor concerned in its production. We have not 

 been able to find any reproductions of tracings obtained previous 

 to the work of Elliott, so that it is difficult to ascertain what was the 

 precise form of curve which was considered to be typical under normal 

 or under different experimental conditions. 



Johansson' found in the dog that the curve presents two summits, 

 and the same is generally true in other animals. 



Lehndorff^ also worked with dogs, and came to the conclusion 

 that the first rise was due to vaso-constriction in the splanchnic 

 area, the "step" to a temporary dilatation of the heart, and the second 

 rise to -increased force and frequency of the heart-beat accompanied 

 by vaso-constriction in the somatic area. 



Elliott,^ who investigated the subject in cats, found that in animals 

 recently admitted and still in a frightened condition the typical 

 splanchnic curve could not be obtained. But he regards the typical 

 curve as something different from that obtained by previous workers 

 in the dog. According to this author a well-known characteristic 

 of the pressure curve seen when the splanchnics are stimulated under 

 good conditions in the cat, is that it rises rapidly for nine or ten 

 seconds; then, without any check in the hearts' rhythm, the curve 

 is sharply cut down nearly to the level from which it came, whence 

 it rises slowly again so long as the stimulus is continued. The drop, 

 according to Elliott, is due to the liberation of adrenin into the blood, 

 and he gives what appears to be fairly complete proof of this. 



'Johnansson, Arch. f. (Anat. u.) Physiol., 1891, p. 193. 



-Lehndorff, Ibid., 1908, p. 362. 



■'Kllioti, joiirn. I'hysiol., 1912, Vol. XLIV, p. 374. 



Sec. 1\', Sig. 'I 



