Histamine was found to be stored in the submandibular gland of the cat mainly in the mast cells. The amine is released from mast cells by compound 48/80 and pilocarpine. This was demonstrated in the in vivo and in vitro experiments and by histological examination. During the physiological stimulation of the gland, via the electrical stimulation of the chorda tympani nerve, significant changes of histamine content were not found. This could be explained by the increased synthesis of histamine during physiological stimulation. The physiological role of histamine in salivary secretion was demonstrated. The similarity between the roles of histamine, mast cells and chromaffine-like cells in salivary and gastric secretion is discussed.

The effects of pilocarpine, compound 48/80 and the electrical stimulation of the chorda tympani nerve on the morphology of the mast cells from the submandibular gland of the cat were studied. All those different treatments of the gland caused the enlargement of the tissue mast cells. We observed also in the glands treated with pilocarpine and compound 48/80 a degranulation of mast cells. The degranulation was more expressed after the application of compound 48/80 to the animals.