Abstract
Summary Morphological and secretory effects of stimulating autonomic nerves have been studied in parotid glands of rats. Sympathetic stimulation evoked a slow flow of saliva which had a high concentration of amylase. After long term sympathetic stimulation secretory granules were heavily depleted from the parotid acinar cells. Parasympathetic stimulation evoked a copious flow of saliva with a low concentration of amylase. However, at high frequency stimulation the total amount of amylase secreted on parasympathetic stimulation was as great or even greater than on sympathetic stimulation, nevertheless, any loss of secretory granules from the acinar cells was very small. It is concluded that secretion of parotid acinar granules in the rat is principally a sympathetic function. Secretion of fluid is more effectively produced by parasympathetic stimulation and much of the amylase in such saliva appears to have arisen from sources other than the secretory granules.