PHARMACOLOGY OF EPINEPHRINE 121 



the capillaries is manifested by its ability to counteract the 

 swelling induced by application to the skin of mustard oil. 

 The leakage through the capillaries caused by histamine and 

 the cutaneous edema caused by paraphenylenediamine may 

 also be prevented by the injection of epinephrine. 639 



Epinephrine when applied directly causes constriction of 

 veins similar to its action on arteries. It is particularly effec- 

 tive in diminishing the calibre of the superficial cutaneous 

 veins. Quiescent rings from the superior vena cava near the 

 heart are stimulated to beat rhythmically when immersed in 

 Ringer's solution containing epinephrine. 258 



The pulse rate of certain invertebrates (Limulus, Daphnia, 

 Peden, Maja, Aplysia, and Salpen) are increased by epineph- 

 rine, while in others (the crab and the snail) the pulse rate 

 is not affected. With large doses the pulse rate of the horse- 

 shoe crab {Limulus), lobster, and snail is decreased. In fish 

 an increased rate and strength of contraction as well as vaso- 

 constriction are observed. In the frog the pressor effect is 

 slight and the effect on the heart rather uncertain unless previ- 

 ously damaged by drugs, in which case it is markedly stimu- 

 lated. 639 



In man the subcutaneous injection of 0.5 to 1 cc. of a 1 : 1000 

 solution of epinephrine causes a slight elevation of blood pres- 

 sure, pallor of the face and extremities, and an accelerated 

 pulse rate. The intracutaneous injection of one cubic centi- 

 meter of a 1 to 10 million solution gives a detectable pallor. 

 A 1 to 1 million solution gives an area of anemia surrounded 

 by a zone of hyperaemia. The subcutaneous injection of 1 

 mgm. of epinephrine in man causes a rise in the systolic pres- 

 sure of the brachial artery of 10 to 30 mms. of mercury. The 

 maximum rise is reached after about one-half hour and ends 

 after an hour or two. The pulse rate is increased 10 to 20 

 beats. Extrasystoles may occur. Euler and Liljestrand 243 

 found the cardiac output of man to increase from 4.3 liters per 

 minute to 7.5 liters following the subcutaneous injection of 



