Desmosomes in the epithelium of human colon

Abstract

Desmosomes in the epithelium of normal human colon show a similar appearance to the desmosomes observed in other epithelia. However we have observed a structural connection between the intercellular lamina and the outer leaflet of the plasma membrane belonging to one of the cells taking part in the formation of this specialised attachment device. This connection occurs at a level which is just outside the desmosomal region. It has also been observed that when the tissue is fixed only in glutaraldehyde the plasma membrane in the desmosomal region stains significantly with uranyl acetate and shows an appearance similar to those obtained after post-fixation with osmium tetroxide. The extradesmosomal plasma membrane, in contrast, does not show any staining with uranyl acetate. The functional significance of these observations have been discussed.