[Effect of pH on the permeability and mechanical properties of intercellular contacts in the small intestinal epithelium].

It is shown that acid site population controlling ion permeation through cell contacts is localized in the region of tight junction. The isoelectric point of cell surface in the region to tight junction changed from mean pH = 2.37 +/- 0.1 for duodenum to pH =2.80 +/- +/- 0.1 for ileum. The maximum of cell adhesion in the tissue reached at mean pH that corresponding the isoelectric point. It seems possible, that this acid site population take part in interaction of plasma membranes of neighbouring cells.