Stimulus effects on protein and electrolyte concentrations in parotid saliva

Twelve subjects collected ten 1 min samples and then a 2.5 ml sample of parotid saliva at a constant flow rate on five separate days with citric acid, salt, sugar, quinine sulphate, and sour lemon drops as gustatory stimuli. The ten 1 min samples were analysed for protein and electrolyte content and the final 2.5 ml sample was used for electrophoretic separation of the different salivary proteins. In most subjects, salt elicited the secretion of saliva with a much higher protein concentration than did the other stimuli, but none of the stimuli differentially influenced the relative proportions of the different proteins secreted. There were several small but statistically significant effects of the nature of the stimulus on the concentrations of sodium, calcium and chloride, but not on potassium, magnesium or phosphate. Since the nature of the gustatory stimulus can influence the composition of saliva, salivary composition could be influenced by the nature of the diet.