Mast Cells and Amines in Normal Ocular Tissues

¹ Department of Ophthalmology, New York University Medical School, New York, N. Y.

Mast cells in the lid and uvea of the rat, guinea pig, rabbit, and monkey were counted, by averaging thecounts in serial histologic sections and multiplying by an appropriate calculated geometric factor. The lid counts are higher than the uveal counts and the iris count is low compared with the remainder of the uvea. Histamine and serotonin contents ivere determined by biochemical assay. The uveal histamine values vary from1.2 to 8.9 µg per gram, and the lid values vary from 11 to 105 µg per gram. The uveal values are at least 10 to 100 times the normal aqueous concentrations of histamine in the literature. Mast cells contain from 1 to 8 µµg of histamine per cell with the exception of the anterior uveal tissues of the rat and rabbit where the histamine-mast cell ratio is one hundred fold higher. The serotonin values of uvea and, lid range from 0.3 to 4.2 µg per gram. Mast cells contain from 0.06 to 0.20 µµg of serotonin per mast cell with the exception of the uveal tissues of the rat and rabbit in which the serotonin mast cell count is Uventyfold higher.