FREEZE-FRACTURE DIFFERENCES IN PLASMA-MEMBRANES OF THE STRATUM-CORNEUM AND REPLACEMENT LAYER CELLS OF AMPHIBIAN EPIDERMIS

A freeze-fracture study of amphibian epidermis has revealed that the outward-facing membrane of the stratum corneum has an extremely dense population of intramembrane particles, whereas the corresponding membrane of the underlying replacement cell layer contains a much lower number of particles. At some time during the molting cycle, therefore, an increase in particle number of the apical plasma membrane of the stratum corneum cell must take place, since none of the other epidermal cell types has such a richly particulate membrane. It is proposed that this high particle density may reflect the high permeability of amphibian stratum corneum to ions and water. © 1979 Academic Press, Inc.