n6 



Effects of Denervation 



partial afferent denervation, unless it be assumed that the chorda 

 contains some afferent fibres from the gland, section of which 

 causes some supersensitivity in the contralateral gland. Hence, a 

 final explanation of the antilytic secretion is still lacking. 



Paroxysmal secretion. This is a type of secretion which like the 

 paralytic and antilytic secretion, can be seen after denervation 

 (Emmelin and Stromblad, 1957, 1958). It differs from these 

 types of secretion in several respects. It is obtained from the 

 parotid gland (of the cat) and is seen in chloralose anaesthesia. It 



70 mm 



Normal 

 Post 1 day 



Minutes 



Fig. 6.3. Paroxysmal secretion. 



Record of drops from the parotid glands of a cat under chloralose anaesthesia. Left auriculo- 

 temporal nerve cut 24 hours before. In each set of tracings, top line, secretion of right gland, no 

 secretion; middle line, secretion of left, denervated gland; bottom line, time (minutes). The 

 lower tracings are immediate continuations of the upper ones (Emmelin and Stromblad, 1958). 



does not occur after preganglionic, but only after postganglionic 

 denervation and then only during the initial stages of nerve de- 

 generation. It seems to have nothing to do with hypersensitivity 

 or adrenaline release. 



When the auriculo-temporal fibres have been cut the paroxys- 

 mal secretion can be seen after one to three days. The salivary 

 flow is not continuous. Periods of secretory activity, in some ex- 

 periments lasting for several hours, sometimes for only ten 

 minutes, alternate with periods of varying length in which there 

 is no flow of saliva. This is illustrated in Fig. 6.3, which shows three 

 consecutive periods of activity one day after postganglionic para- 

 sympathetic denervation of a parotid gland. From the contralateral, 



