HUMAN SALIVARY-GLAND PARENCHYMAL-CELLS SEEN BY SEM FROM THE CYTOPLASMIC SIDE USING A NEW OSMIUM MACERATION METHOD

By removing all or most organelles, we have exposed the cytoplasmic si de of the plasmalemma and its specializations in serous cells and in c ells of striated and excretory ducts of human major salivary glands. T he areas of plasmalemma located beneath the lumen and those bordering the intercellular canaliculi are covered by evenly distributed particl es arranged in a continuous band and, below it, in regularly spaced cl usters. A similar pattern of particles is seen on the internal aspects of the juxtaluminal plasmalemma of cells of both striated and excreto ry ducts. Small isolated clusters of particles are seen in other regio ns of serous and ductal cells as well, being particularly numerous alo ng the basal processes of cells of striated ducts. A distribution of p articles resembling that present along intercellular canaliculi of ser ous cells also is seen on the plasmalemma bordering the biliary canali culi where, however, the clusters look smaller and farther apart. Larg e clusters of particles, matching those seen on salivary glands and on liver, are present at the base of the short processes of cells of the stratum spinosum of squamous stratified epithelia. Since the sites of location of the clusters closely correspond to the areas where transm ission electron microscopy (TEM) reveals the presence of desmosomes, w e believe that the clusters may be related to these cellular junctions . Of more difficult interpretation are the particles present on the ju xtaluminal band corresponding both to the zonula occludens and to the zonula adhaerens.