Distribution of interstitial cells of Cajal and gap junction protein, Cx 43 in the stomach of wild-type and W/Wv mutant mice.

The distribution of different subtypes of interstitial cells of Cajal (ICC) in the tunica muscularis of the stomach of wild-type and W/W (v) mice was studied by immunohistochemical staining for Kit. Special attention was also given to the distribution of the gap junction protein connexin 43 (Cx 43) immunoreactivity. Kit-immunoreactive cells of the circular and longitudinal muscle layers (ICC-CM and ICC-LM) were densely distributed throughout the cardia, fundus, the squamous epithelial portion of the corpus and the pylorus, but they were decreased in number within the glandular epithelial portion of the corpus. Kit-immunoreactive cells of the myenteric region (ICC-AP) emerged slightly proximal to the squamous-glandular epithelial transition and increased in number towards the pylorus. Kit-positive cells were also observed at the submucosal border of the circular muscle layer (ICC-SM). ICC-CM and ICC-LM were not observed in the stomachs of W/W (v) mice, but a few ICC-AP were observed in the pylorus. Cx 43 immunoreactive deposits were only sparsely distributed in the circular muscle layers of the cardia, fundus and the squamous epithelial portion of corpus. However, the Cx 43 immunoreactive deposits were densely distributed in the glandular epithelial portion of the corpus that contained fewer ICC-CM. Cx 43 immunoreactive deposits were rare in the circular muscle layer of the pylorus. No Cx 43 immunoreactivity was detected in the longitudinal muscle layer throughout the whole stomach. The distribution of Cx 43 immunoreactivity in the W/W (v) mouse stomach was almost the same as in wild-type mice. The functional significance of each type of ICC at each region is discussed in reference to regional differences in the distribution of both ICC and Cx 43, and differences between wild-type and W/W (v) mice.