INTERSTITIAL-CELLS OF CAJAL IN THE GUINEA-PIG GASTROINTESTINAL-TRACT AS REVEALED BY C-KIT IMMUNOHISTOCHEMISTRY

Interstitial cells of Cajal (ICC) of various morphologies have been de scribed in the gastrointestinal (GI) tracts of mammals. Different clas ses of ICC are likely to have different functional roles. ICC of the m ouse GI tract have been shown to express c-kit, a proto-oncogene that codes for a receptor tyrosine kinase. We have studied the distribution of ICC within the guinea pig GI tract using antibodies to c-Kit prote in and immunohistochemical techniques. c-Kit-like immunoreactivity rev ealed at least 6 types of ICC: (1) intramuscular ICC (IC-IM1) that lie within the muscle layers of the esophagus, stomach, and cecum, (2) IC C within the myenteric plexus region (IC-MY1) in the corpus, antrum, s mall intestine, and colon, (3) ICC that populate the deep muscular ple xus of the small intestine (IC-DMP), (4) ICC at the submucosal surface of the circular muscle layer in the colon (IC-SM), (5) stellate ICC t hat are closely associated with the myenteric plexus (IC-MY2) and orie ntated toward the longitudinal muscle layer in the colon, and (6) bran ching intramuscular TCC (IC-IM2) in the proximal colon within the circ ular and longitudinal muscle layers. c-Kit immunohistochemistry appear s to be an excellent and selective technique for labeling ICC of the g uinea-pig GI tract. Labeling of these cells at the light-microscopic l evel provides an opportunity for characterizing the distribution, dens ity, organization, and relationship between ICC and other cell types.