198 



Theories of Secretion 



also prevented the potential from appearing while the vasodilator 

 action was not markedly affected. The potential was also not due 

 primarily to flow of secretion since essentially the same changes 

 were found when the duct was clamped and saliva not per- 

 mitted to flow. There seems little doubt that the gland electro- 

 gram is a concomitant of secretory activity in the gland cell 

 (Bayliss and Bradford, 1886; Bradford, 1887, 1888; Harreveld, 



I930)- 



The electrogram has subsequently been studied by other workers 



and the results obtained comprehensively reviewed by Langen- 

 skiold (1941) and Lundberg (1958). Both parasympathetic and 

 sympathetic stimulation yields complicated potential patterns dur- 

 ing and following stimulation (Figs. 10. 1 and 10.2). Apart from 

 the initial sign of the potential which is consistent, the rest of the 

 complex is extremely variable between individual glands and is 



Fig. 10.2. The same gland as Fig. 10. 1 but responses to stimulation 

 of the cervical sympathetic nerve. 



(Lundberg, I955-) 



