PHARMACOLOGY AND TOXICOLOGY OF SUPRARENALS 241 



There are differences in the response of the uterus in different species. 

 The rabbit's uterus whether pregnant or not is stimulated to contraction by 

 epinephrin (Langley(a) ). The reverse effect is produced in the uterus of 

 the rat and guinea pig, epinephrin causing inhibition whether or not preg- 

 nancy exists. However, the uterus of the cat when pregnant is con- 

 tracted and when non-pregnant is relaxed under the influence of epineph- 

 rin (Cushny(a), Dale). 



The isolated uterus because of its great sensitivity has been used as 

 a quantitative test for epinephrin (Frankel). By this means dilutions of 

 1 :20,000,000 may be de- 

 tected. 



Response of the 

 Bronchioles. Although 

 there appears to be some 

 uncertainty as to the ac- 

 tion of epinephrin on the 

 bronchioles there are 

 numerous clinical obser- 

 vations that it relieves 

 the spasm of bronchial 

 asthma (Kaplan, Jagic). 

 It seems that when the 

 bronchioles are in a con- 

 dition of tonic contrac- 

 tion epinephrin will cause 

 considerable dilatation. 

 Dixon and Ransom found 

 that when the bronchioles Fig. 2. Lung volume above, blood-pressure below, 



were not fnllv rplaxprl Urethane anesthesia. 'A, Accelerator bundle stimu- 

 m y lated by faradic current; B, Electrical stimulation of 



epinephrin dilated them vagus; C, Injection of 1.0 c.c., 1:10,000 epinephrin. 



to the maximum. How- J^ ^/ sio T) nd8 ' (After Dix n and RanS m ' Am ' 

 ever, Golla and Symes 



have usually obtained constriction of the bronchioles from epinephrin un- 

 less constriction had previously been established by some other drug. They 

 suggest that the usual action is constriction while the use of some drug 

 which previously constricted reversed the action. In rebuttal the experi- 

 ment of Dixon and Ransom may be cited in which they obtained epineph- 

 rin dilatation of the bronchioles after constriction of the latter through 

 vagus stimulation (Fig. 2). This would indicate that the state of con- 

 traction of the muscle is the determining factor. 



Paralysis of the constrictors by ergotoxin enables epinephrin to pro- 

 duce dilatation of the bronchioles with greater ease. Jackson (&) (d) (e), 

 however, found that ergotoxin possessed no very marked specific action on 

 the bronchioles. The negative results of many investigators may be due to 



