210 



Theories of Secretion 



saliva 



3C 

 20 



w 



cps 



-4 



-2 



'£?//. 



40 50 60 70 80 SO WO 



mm 



Fig. io.io. A similar experiment to that shown in Fig. 10.9. 



Kcell refers to the total gland potassium in mEq ; g calculated from the potassium balance and 

 direct gland analysis at 100 minutes. Kv and Ksaliva are the concentration of potassium in the 

 venous blood and saliva respectively. The arterial plasma potassium was 42 mEq 1. Stimulation 

 was started at 2 c/s, saliva and venous transients ensued and the gland potassium content declined 

 from 82 mEq/g to 75 mEq/g. The stimulation frequency was then increased to 20 c/s without 

 interruption of stimulation. A further saliva and venous transient ensued and the gland content 

 abruptly fell by a further 10 mEq/g. Reduction of stimulation frequency to 7 c/s did not produce 

 any striking change. On cessation of stimulation the gland began to recover its potassium con- 

 centration (Seeman, 1956). 



could not be due to acinar secretion although the later phase could 

 very well be acinar in origin. They then made the assumption 

 that since this saliva was of duct origin, potassium must accumulate 

 in the duct lumen during the rest period. This theory, however, is 

 totally unable to explain the appearance of a potassium transient 

 on changing the rate of nerve stimulation nor the dependence of 

 the magnitude of the transient on the rate of stimulation following 



