The non-mast cell histamine in the submandibular gland of the cat.

The submandibular gland of the cat contains the typical mast cells. In these cells most of the tissue histamine is stored, and the non-mast histamine adds only a smaller part (10%) of the total histamine content in the gland. However, the stimulation of the gland (nerve stimulation, i.a. application of pilocarpine or compound 48/80) increases the non-mast cell histamine as calculated from the correlation between histamine and mast cell contents of the gland. The free histamine is taken up by different tissues of the cat and its methylated metabolite, N tau-methylhistamine, is formed. The cholinergic stimulation of the tissues causes a decrease of methylation of histamine indicating a decrease of the uptake of the amine into the cells.