Bacterial agglutinins in rat salivary glands: effect of glandular stimulation and calcium dependency

Abstract

The secretory pattern of salivary, bacterial agglutinins was studied in the rat. The three major salivary glands were cannulated bilaterally and their secretions collected separately after parasympathomimetic and sympathetic stimulation. The bacterial aggregating activity of the secretions was tested against four strains of bacteria indigenous to the rat. Agglutinin activity was demonstrated in both parasympathomimetic and sympathetic secretions. The parotid glands tended to show the highest total output of agglutinins, with the highest titers found in parotid saliva on sympathetic stimulation. In submandibular and, particularly, parotid saliva, titers tended to increase when stimulation with pilocarpine was followed by sympathetic stimulation. In contrast, titers in sublingual saliva tended to decrease on sympathetic stimulation. When expressed as titer output per minute, sympathetic parotid secretion showed the highest agglutinin activity. Agglutinin activity appeared unrelated to total protein or to duct-derived amidolytic activity. Titers of parotid or submandibular saliva were increased 5-to 10-fold by the presence of 3.3 mM CaCl₂ in the reaction mixture. By contrast, the agglutinating activity of sublingual saliva on parasympathomimetic stimulation was unaffected by extraneous CaCl₂. Measurements of Ca concentration in similarly obtained rat salivary secretions did not show patterns of Ca concentration that could be related to the varying sensitivity of the agglutinating activity to Ca.