Aad. Santos et Crs. Machado, HISTOCHEMICAL AND ULTRASTRUCTURAL STUDIES OF MAST-CELLS IN THE INTESTINAL-MUCOSA AND SKIN OF THE OPOSSUM DIDELPHIS-ALBIVENTRIS, Histochemical Journal, 26(3), 1994, pp. 233-238
The mast cells located in the intestinal mucosa of a non-eutherian mam
mal were studied in comparison with those in the skin of the ear. In t
he intestinal mucosa, the mast cells exhibited a more variable shape,
larger cytoplasmic granules and greater sensitivity to fixatives regar
ding their staining towards Toluidine Blue. Ultrastructurally, these g
ranules were more heterogeneous but lacked the crystalline content fou
nd in granules of skin mast cells; lipid body-like organelles were fou
nd only in the mucosa-located mast cells. Histochemically, they differ
ed from skin mast cells by the absence of periodic acid-Schiff (PAS)-p
ositive granules. Unlike the mucosal mast cells of the rat, they fluor
esced brilliant yellow after berberine treatment, which is evidence of
the presence of heparin.