Salivary Rest Transients 207 



until the steady level of only 8-20 mEq/1. is reached. On closer 

 examination of this transient, it can be seen that it has two phases 

 (Fig. 10.8). It rises to a peak with a very short latency and then 

 falls quite rapidly in about 20 seconds. The rate of fall then be- 

 comes very much slower and a steady state is reached only after 

 1-2 ml. saliva/g. gland has been secreted. Lundberg (1958) has 



Cpm/drop 



20,000 



15,000 

 1 0,000 



5,00Qv> 

 5000*" 



4000 

 3000 

 2000 

 1000 



.0 0—0— o- 



■1 



\ 



50 



100 



150 



sec 



200 250 300 



350 



Fig. 10.8. Rest transients of iodide and potassium in the parotid saliva of 



the dog. 



Notice the notch in the falling limb of the potassium record separating the early phase from 

 the later prolonged phase, which lasts for about 220 seconds. The rest period was 31 minutes. 

 The abscissa gives the time from the start of stimulation (Burgen, Terroux and Gonder, 1959). 



reported finding similar transients in the sublingual gland. Both 

 phases of this transient are dependent on the period of rest the 

 gland has had since the previous period of stimulation ; in the case 

 of the dog parotid, half recovery of the first phase occurs after a rest 

 period of 2-5 minutes ; in the dog submaxillary, recovery is much 

 slower (half time 15-30 minutes) (Seeman, 1956). Brusilow and 

 Cooke (1959) did not find appreciable potassium transients when 

 using very brief periods (less than 1 minute) in the dog parotid 



