Adherens junctions and desmosomes

Narrowing of the intercellular space = about 5nm where the cadherins couple

I am not sure why the intercellular space is recorded by What When How as different dimensions (beside the adherens junctions 25nm vs 20nm, the height of the adherens junction itself) and of the intercellular space beside the cardiac desmosome as 35nm and the height of the desmosomal intercellular space as 20-25nm. It seems to me that if one is comparing intercellular space heights, that one really needs to set some parameters and get some comparisons. This could be a massive job, as there are so many variables, not to mention fixation parameters, tangential sections, membrane proteins, cell types and where on the plasmalemma one is going to attempt to measure.
Just in four desmosomes (between hepatocytes from syrian hamster) all fixed the same, similar ages and reasonably good section orientation the following is clear.
1. the intercellular space is pretty variable
2. desmosomes are going to have a slightly smaller intercellular dimension than adjacent intercellular space
3. the center dense line extends beyond the outer desomosomal plaque proteins
4. there is a density in the plasmalemmae as an annulus or ring around the desmosome but intercellular space is wide
5. the separation of leaflets of the desomosomal plasmalemma is just a little more distinct than distant plasmalemma
6. the outer leaflet of the plasmalemma at the desomosoe seems to be quite rigid

See below, four examples and the relative wide range of reduction in intercellular space. Syrian hamster — routine electron microscopy, red dots intercellular space remote from the desomosome, blue dots height of intercellular space at the desmosome. Two of the images – right top and bottom – have double mitochondrial tethers. Left side images have a single mitochondrial tether. Right top and bottom have cross and longitudinal sections of intermediate filaments, respectively adjacent to the mitochondria. In both cases the outer mitochondrial membrane also has a rigid look.