Morphological changes in the myoepithelial cells of the rat sublingual salivary gland during differentiation as shown by the nitrobenzoxadiazole-phallacidin fluorescent method.

Changes in myoepithelial cells (MECs) during perinatal development were examined by using the fluorescent probe for actin, nitrobenzoxadiazole (NBD)-phallacidin. By the twentieth day of gestation, there was no distinct fluorescent pattern suggestive of MECs. In newborn and 1-day-old rats, cells with diffuse fluorescence occurred around the acini, representing incipient MECs. Between 3 and 4 days after birth, actin staining was concentrated in strands which were arranged parallel to the long axis of the cell processes. MECs had developed further by the tenth day after birth with an increased number and thickness of their processes. Fully developed MECs were found between the thirtieth and fortieth day. These were stellate and encompassed individual acini.