PHAKMACOLOGY AKD TOXICOLOGY OF SUPRAKENALS 239 



In spite of the effect which epinephrin may have upon the circu- 

 lation, it may also affect the smooth muscle of the canal for the inhibi- 

 tion is not necessarily synchronous with the pallor of the intestine (Lang- 

 ley(a)). 



The two effects, inhibition and stimulation, seem to depend upon the 

 dosage of epinephrin, for it has been shown by Hoskins(e) (Fig. 1) that 

 doses just below the threshold for inhibition will frequently cause an in- 

 creased tonus as well as an increased rhythmical activity. 



The power of inhibition in the intestine has been used as a quantitative 

 test for epinephrin. 



The response of other parts of the tract is similar to that of the in- 

 testine except that the pyloric, ileo-colic and internal anal sphincters are 

 contracted just as though stimulated by 

 the sympathetic nerves (Elliott (&)). 

 The rabbit is an exception to this in the 

 case of the cardiac and internal anal 

 sphincters, epinephrin causing relaxa- 

 tion. In this animal epinephrin pro- 

 duces relaxation of the esophagus and 

 marked inhibition of the large intestine. 

 The sympathetic nerves in birds and 

 amphibia are mainly motor in function. 

 Here epinephrin causes constriction 

 (Dixon), further corroborating the gen- 

 eralization that epinephrin, if it acts at 

 all, produces a response identical with 

 sympathetic stimulation. The esoph- 

 agus of the frog and toad appears to 

 differ from other parts of the alimentary 

 canal, being inhibited by epinephrin 

 (Boruttau). In the fowl the large intestine is relaxed while other parts 

 of the canal are contracted. Here also stimulation of the spinal roots of 

 the sympathetic nerves acts likewise. 



Loeper and Verpy suggest that there may be digestive syndromes 

 originating from the suprarenal. They found that the intramuscular in- 

 jection of 1 mgm. of epinephrin in human subjects caused an increase 

 in the secretion of HC1 in the stomach as well as augmentation and ac- 

 celeration of the contractions in the digestive tract. 



Response of Ureter, Bladder and Urethra. Intravenous injections 

 of epinephrin cause little effect in the bladder of the dog, rabbit, rat, 

 hedgehog and guinea pig. The effect is also slight in the monkey 

 (rhesus), relaxation occurring to a small degree. On the other hand 

 marked effects are produced in the cat (Lewandowsky(fr)), goat and ferret, 

 relaxation being produced in the first and contraction in the last two 



Fig. 1. One-half the original size. 

 A segment of the small intestine of 

 the rabbit beating in, A, Ringer's 

 solution; B, Ringer's solution; C, 

 epinephrin 1:1,000,000,000; D, Ring- 

 er's solution; E, epinephrin 1:500,- 

 000,000; F, Ringer's solution diluent 

 in C and E, Ringer's solution. Time 

 = 30 seconds. (After Hoskins, Am. 

 J. Physiol.) 



