Comparison of rat salivas evoked by auriculo-temporal and pilocarpine stimulation

Abstract

Stimulation of rat parotid gland by way of the auriculotemporal nerve was used to delineate the relationship between flow rate and concentration of Na and K in the saliva. It was found that [Na] increased with increasing flow rate, whereas [K] hardly changed. Comparison of the electrolyte composition of saliva evoked by supramaximal stimulation of the nerve with that evoked by supramaximal doses of pilocarpine showed only small differences in [Na] and [K], and these were attributable to differences in flow rate. On the other hand, levels of amylase activity and total protein were 5–20 times higher in pilocarpine-evoked saliva than in saliva obtained by stimulation of the auriculotemporal nerve; these differences could not be attributed to differences in flow rate. Pilocarpine is, therefore, an adequate substitute for stimulation of the parotid gland by the parasympathetic nerve if only electrolytes and flow rate are considered, and is not a satisfactory substitute when the protein and amylase activity are considered.