Chemical Changes 105 



amount. Changes in the demilune cells, the alveolar cells and the 

 striated ducts give the gland a characteristic picture, which has 

 been examined by many investigators, e.g. Heidenhain (1868), 

 Langley (18856), Krause (1897), Maximow (1901), Gerhardt (1903), 

 Rawlinson (1935a and b). Similar histological changes are found 

 in a normally innervated gland of an animal treated for some time 

 with atropine. When the treatment is discontinued the gland re- 

 gains its normal histological appearance. The changes brought 

 about by prolonged atropinization are thus reversible. This is true 

 also for those obtained after section of the chorda, for after treat- 

 ment with pilocarpine for a few days the picture of a gland, whose 

 chorda had been cut in advance, is fairly normal (Emmelin, 

 Jacobsohn and Muren, 1951). 



CHEMICAL CHANGES 



Little is known of the changes in chemical composition which 

 occur in a salivary gland after denervation. Systematic investiga- 

 tions have concerned mainly the activity of cholinesterase and 

 amine oxidase (Stromblad, 19550, 1956c and d). Because of the 

 pronounced atrophy resulting from parasympathetic denervation 

 it is necessary to calculate the activity both per total gland and as 

 a concentration. The results of Stromblad's work may be sum- 

 marized briefly as follows. 



The total activity of cholinesterase, mainly due to true choline- 

 sterase, and of amine oxidase, decreases on preganglionic, para- 

 sympathetic denervation on about 30 or 40 per cent. This corre- 

 sponds approximately to the loss in weight. Postganglionic, 

 parasympathetic denervation (carried out in parotid glands) has 

 a more striking effect on the cholinesterase; the total amount is 

 reduced by about 55 per cent, the concentration about 50 per cent. 

 The amine oxidase, on the other hand, is less affected by this 

 operation. 



Extirpation of the superior cervical ganglion does not reduce the 

 amine oxidase activity. Indeed in the parotid gland there may be 

 an increase. 



It may be added that in the absence of nerve section treatment 

 with a parasympatholytic agent reduces the amine oxidase activity 

 but does not affect the cholinesterase activity. In a parasympa- 

 thetically denervated gland treatment with pilocarpine tends to 

 restore the activity of the two enzymes. 



