422 IMMUNO-CATALYSIS 



However, in evaluating the possible concentration of acetylcholine 

 which may accumulate in the shock organs the tremendous difference 

 in the concentration of cholinesterase present in the motor end-plates 

 and in the mammalian muscle should be taken into account. It has 

 been calculated that in the muscle the time of hydrolysis of acetylcho- 

 line is 40,000 times longer than in the end-plates (Nachmansohn, 

 1945). Due to this great difference, the accumulation of a toxic 

 amount of acetylcholine in the muscle during or preceding a shock 

 may not appear to be an impossibility. 



h. Liberation of Acetylcholine in Anaphylactic Shock. Went and 

 Lissak (1936) reported that choline-like substances are liberated 

 during an anaphylactic shock from the heart muscle. The perfused 

 heart of the sensitized guinea pig showed slowing and rhythmless re- 

 action when antigen was added to the perfusion fluid. This effect was 

 prevented by the perfusion of the heart with Tyrode's solution con- 

 taining atropine. This effect was not produced by histamine. In the 

 heart perfusate of a guinea pig surviving anaphylactic shock a much 

 larger amount of choline was found than in normal heart muscle. The 

 choline contents of the heart muscles of normal, sensitized and de- 

 sensitized animals (the heart muscle of surviving guinea pigs) were 

 alike. In contrast, the heart of the shocked animal contained a lesser 

 amount of choline. On the other hand, the histamine content of all 

 the three types of heart muscle remained the same. Acetylation of 

 the perfusion fluid obtained in these experiments yielded a substance 

 possessing properties comparable to those of acetylcholine in its action 

 on the frog heart and on the leech. Farber, et al. (1944) reported the 

 liberation of a noteworthy amount of acetylcholine in the shocked 

 heart and none in extracts of normal heart. There was no difference in 

 the amounts of acetylcholine found in the shocked and normal lungs 

 and intestines of guinea pigs. 



It has been reported that the antihistaminic drug 933F prevents the 

 action of epinephrine, acetylcholine and histamine. The concentration 

 of 93 3F required were in the following order: 



Histamine > acetylcholine > epinephrine 



Antergan (2399RP) was found to have no action on adrenalin, but 

 inhibited acetylcholine and histamine action on the intestine and 

 pregnant uterus of the guinea pig. It has a hypotensive effect itself 



