1.   Small gap junctions were observed between gastric surface mucous cells in all healthy volunteers.

2.   Therefore, we decided to compare gap junctions between gastric surface mucous cells of gastric ulcer patients with those of healthy volunteers.

3.   In healthy volunteers, small gap junctions were often identified on the lateral plasmalemma of gastric surface mucous cells, mainly at the level of the cell nucleus.

4.   The frequency of gap junctions in the gastric surface mucous cells of the patients with gastric ulcers and of healthy volunteers is shown in Table II.

5.   The results of our freeze fracture method clearly showed significantly fewer gap junctions between gastric surface mucous cells in patients with gastric ulcer than in healthy volunteers.

6.   Morphologically, this barrier is provided principally with tight junctions between gastric surface mucous cells.