PHARMACOLOGY OF EPINEPHRINE 125 



light or to eserin. 451 The reaction by which stimulation of 

 the dilator pupillae and inhibition of the sphincter iridis occurs 

 in response to epinephrine is ten times more sensitive in the 

 cat than in the rabbit. In the dog, due to stimulation of the 

 oculomotor center, one often obtains contraction of the pupil 

 instead of dilatation. 



Muller's muscle is contracted by epinephrine making the 

 globe of the eye more prominent and enlarging the palpebral 

 fissure. 



UTERUS 



The action of epinephrine on the uterus is most striking. 

 Uterine anemia and violent contractions are elicited in animals 

 which, if pregnant, may be made to abort. The uterus is also 

 rendered more excitable to physiological or artificial stimuli. 



The effect of epinephrine on the uterus varies with different 

 animal species. The rabbit's uterus is stimulated whether 

 pregnant or not. Inhibition is caused in the gravid or non- 

 gravid uterus of the mouse, rat, or guinea pig. The uterus of 

 the pregnant cat is contracted while the non-pregnant uterus 

 is relaxed. In the dog, if pregnant, stimulation results; if 

 non-pregnant, stimulation is followed by relaxation and 

 inhibition. Similar results are obtained in the sow. The 

 non-gravid uteri of the cow, ferret, and monkey are stimulated 

 by epinephrine. 



According to Bourne and Burn, 76 the uterine movements of 

 the intact pregnant human uterus are inhibited by tolerable 

 doses of epinephrine. Most authors, on the other hand, re- 

 ported stimulation of the human uterus whether gravid or non- 

 gravid, but these results were based on experiments in which 

 large doses of epinephrine were applied to strips of muscle re- 

 moved at operation. 



As we have seen in Chapter VI, strips of uterine muscle are 

 frequently used in the biological assay of epinephrine. 



The above described reactions of the uterus under different 



