Patterns of junctional communication in skin.

The patterns of junctional communication in whole skin have been studied by iontophoretic injection of the fluorescent dye Lucifer Yellow CH into excised strips of tissue from newborn (less than 48-h) mice. Sections of injected specimens embedded in resin show that: coupling in the dermis is extensive, the injected dye spreads to more than 500 cells in 5 min; coupling in the epidermis is more restricted, dye spreads to less than 25 cells in 5 min; cells of the epidermis are not detectably dye-coupled to the cells of the dermis except at occasional restricted sites, probably related to hair follicle development; immature sebaceous gland cells are coupled but appear to be isolated from other cell types; and endothelial cells in the dermis are coupled to surrounding fibroblasts.