Lateral membrane morphology and gap junction structure in rabbit corneal endothelium

Abstract

The morphology and the intercellular contacts of the lateral plasma membranes in the rabbit corneal endothelium have been observed by the lanthanum tracer technique. When the lateral cell boundaries show extensive interdigitation, they also send bulbous projections from one cell into its neighbor and gap junctions bridge the lateral plasma membranes. The basic features of the intercellular contacts are similar to the typical gap junction, having a polygonal array of subunits with a center-to-center spacing of about 90 Å bridging a narrow intercellular space. In many of the junctions observed two additional features are prominent: the subunits form linear arrays and the intercellular space within the junction shows a periodic, 320–360 Å center-to-center, widening. The latter feature appears as lanthanum-filled channels where the narrow intercellular space with the subunit array widens from 30–40 to 60–80 Å.