152 The Inorganic Components of Saliva 



represents a genuine change in the potassium secretory process. 

 The concentration of potassium in saliva evoked by sympathetic 

 stimulation or adrenaline injection is about twice that of chorda 

 saliva; there are, however, no striking after-effects of the adrena- 

 line on subsequent chorda stimulation (Langstroth, McRae and 

 Stavraky, 19386; Kesztyiis and Martin, 1937). No studies have 

 been reported on the secretion of rubidium and caesium ,in the 

 saliva. 



SODIUM AND LITHIUM 



In those glands producing a hypotonic saliva, the concentration 

 of sodium is highly dependent on the rate of saliva flow (Fig. 8.4; 

 Gregersen and Ingalls, 1931; Langstroth, McRae and Stavraky, 

 19380; Thaysen, Thorn and Schwartz, 1954; Hildes, 1955; Pra- 

 der, Gautier, Gautier and Naef, 1955; Brusilow and Cooke, 1959). 

 At low flow rates the concentration may be as little as 1-5 mEq/1. 

 and rises to 100 mEq/1. or more at the highest rates of secretion. 

 In some glands, a rise of sodium concentration may occur also at 

 very low flow rates. The flow dependence of saliva sodium concen- 

 trations makes it impossible to give any narrow normal range of 

 concentrations but, despite this, values for sodium in resting saliva 

 in man may be of use. In the small flow range involved, the varia- 

 tions of sodium concentration are relatively small. For instance, 

 Prader and Gautier (1955) found that the resting saliva of normal 

 children contained 2-15 mEq/1. of sodium, whereas the saliva 

 from children with cystic fibrosis of the pancreas contained 20-45 

 mEq/1. Similarly, changes in sodium concentration consequent on 

 altered adrenocortical secretion may be quite consistent with rest- 

 ing flows although no consistent change may be found at high 

 rates of secretion (Grad, 1952; White, Entmacher, Rubin and 

 Leiter, 1955; Martin, 1958). In saliva produced by sympathetic 

 stimulation, sodium concentrations are considerably higher than 

 at the corresponding flow rates produced by chorda stimulation 

 but they remain hypotonic (Langstroth, McRae and Stavraky, 

 19386). In glands with an isotonic secretion such as the cat sub- 

 lingual and rat parotid sodium is the predominant cation and is 

 present at a concentration of 140-160 mEq/1. (Lundberg, 1958; 

 Schneyer and Schneyer, 1959). 



Brusilow and Cooke (1959) have reported that following brief 

 interruption of regular stimulation, the secretion of sodium in the 



