Observations on the Amylase Content and Flow Rate of Human Saliva Following Gustatory Stimulation

Abstract

Parotid saliva was collected free of bacterial contamination (tested by culture on blood agar) using a suction cup placed over the orifice of the duct. The effect of 4 gustatory modalities (sour, salty, sweet and bitter) was tested on a group of 17 adult subjects by applying solutions of the stimulant to the dorsum and lateral borders of the tongue every 20 seconds for 5 to 10 minutes, using a cotton swab. Samples were collected about one hour after lunch. Salivary amylase was assayed by measuring loss of starch-iodine color, compared to commercial alpha amylase standards following a 5 minute incubation at 37[degree]C. The following were the results of 3 separate samples from 17 subjects: 3% citric acid, 50 amylase units, 0.60 ml/min. 40% sucrose, 65 amylase units, 0.26 ml/min. 30% saline, 53 amylase units, 0.47 ml/min. 0.15% quinine sulfate, 50 amylase units, 0.24 ml/min. In addition, a pronounced variation of the amylase content of saliva between individuals has been confirmed. Analysis of variants also demonstrated significant differences between gustatory stimuli. However, most of this effect seemed to be in the 40% sucrose stimulus, as compared to the mean of the other three stimuli. The amylase content of saliva showed no correlation with the rate of secretion over a flow rate increase of 2.5 times.