442 IMMUNO-CATALYSIS 



system, is followed by gradual fall in blood pressure (parasympathetic 

 response) due to peripheral vasomotor paralysis. There is dyspnea, 

 vomiting, salivation, diarrhea, etc. which indicate excessive stimulation 

 of glandular secretions. Agonal convulsion is characteristic of anaphy- 

 laxis, arising, possibly, from severe anoxia or lack of oxygen supply, 

 heart block, hypoglycemia, increased intracranial pressure, etc. 



The shock reactions caused by antigen-antibody combinations, 

 histamine, acetylcholine, peptone-like substances, certain proteinases, 

 and trauma possess more or less close resemblances. It would seem that 

 interference or blocking of pulmonary, circulatory and glandular 

 functions of the organism may be the principal reactions occurring in 

 shock. Other manifestations in shock associated with or resulting from 

 them may appear to be byproducts which no doubt can intensify the 

 course of events and precipitate fatal shock. 



The specific factors which have been claimed to be responsible for 

 the various reactions occurring in shock are histamine, acetylcholine 

 and tissue proteolytic enzymes. These are individually discussed. At 

 present the specific data are inadequate to consider specifically any one 

 of these three factors as the one solely responsible for the phenomena 

 of shock. It may be that all these factors are jointly involved. 



In this connection it may be worth while to point out that while 

 the role of proteinases in the living cell is well known, the specific 

 nature of their activity in a cell injured by an antigen-antibody reaction 

 is not known. In our opinion, in such a cell proteolytic enzymes could 

 function prinicipally as catabolic agents. In other words, the hydrolytic 

 role of proteinases may supersede those of their synthetic functions. In 

 an in vitro environment proteinases exercise on proteins principally 

 a hydrolytic function. An injured cell in this respect may be compared 

 to an in vitro environment. This may appear plausible in view of the 

 fact that an injured cell, as in a shock, would be cut off from the flow 

 of energy required for synthetic processes. 



On comparing the anaphylactic reactions provoked by histamine and 

 acetylcholine, we see a very close resemblance between the two in 

 these respects. However, while acetylcholine plays an indispensable role 

 in the normal function of the autonomic nervous system and those of 

 voluntary muscles, and the mechanism of its action is characterized, 

 there is as yet no information concerning the normal function, if any, 

 or the specific receptor site for histamine action. 



