CHAPTER V 



The Actions of Narcotics 



Introduction 



In this chapter we shall deal with the action of narcotics 

 on cells. This group of substances has not been studied 

 as intensively by such a large number of chemists as have 

 vesicants, but on the other hand it has been studied by 

 people with much more diverse backgrounds. As a result 

 there has been a very fruitful interplay of physical and 

 chemical theories and a great variety of working hypo- 

 theses has been considered. Most of these hypotheses 

 fall into three broad groups. The first of these involves 

 an action on the cell surface or some other biologically 

 important surface. The second emphasises the partition 

 of narcotics between an aqueous phase and other phases 

 of a lipoid character. The third considers narcotics as 

 substances whose action is mediated primarily through 

 enzyme systems. 



Before proceeding in further detail, it will be as well 

 to get some idea of what is referred to under the heading 

 of narcosis. It is not a word with a single precise meaning. 

 It includes such phenomena as the loss of consciousness, 

 inhibition of a reflex, inhibition of the contractility of, 



