They also
suggested that the clustered intramembranous
particles of the P-face shown in Fig. 3 of Sardet
et al. (’79) are gap junctions although they are not
recognized as such. Unfortunately, this figure
shows the fracture face of the apical membranes of
two neighboring pavement cells and not the
lateral membranes as would be necessary to make
such a claim. It is possible that gap junctions in
primary cultures are an artefact of being under
culture conditions as in situ attempts to demonstrate
dye-coupling were unsuccessful due to
technique reasons (mucus layer). Thus, further
work seems justified to clarify this important
question.