Characterization of interstitial cells of Cajal in the subserosal layer of the guinea-pig colon.
Interstitial cells of Cajal in the subserosa (ICC-SS) of the guinea-pig proximal colon were studied by immunohistochemistry for c-Kit receptors and by transmission electron microscopy. These cells were distributed within a thin layer of connective tissue space immediately beneath the mesothelium and were multipolar with about five primary cytoplasmic processes that divided further into secondary and tertiary processes to form a two-dimensional network. Ultrastructural observations revealed that ICC-SS were connected to each other via gap junctions. They also formed close contacts and peg-and-socket junctions with smooth muscle cells. Three-dimensional analysis of confocal micrographs revealed that the cytoplasmic processes of ICC-SS had contacts with interstitial cells in the longitudinal muscle layer. Taking account of the location and peculiar arrangement of the ICC-SS and the main functions of the proximal colon, i.e. the absorption and transport of fluids, we suggest that the superficial network of ICC-SS acts as a stretch receptor to detect circumferential expansion and swelling of the colon wall and triggers the contraction of the longitudinal muscle to accelerate the drainage of fluids from the colon.
Aranishi
Hiromi
H
Laboratory of Histology and Neuroscience, Department of Health Science and Social Welfare, Faculty of Human Sciences, Waseda University, 2-579-15 Mikajima, Tokorozawa, Saitama 359-1192, Japan.
Kunisawa
Yumi
Y
Komuro
Terumasa
T
D000818:Animals; D003106:Colon / Q000502:physiology / Q000648:ultrastructure*; D005260:Female; D017629:Gap Junctions / Q000648:ultrastructure*; D006168:Guinea Pigs; D007413:Intestinal Mucosa / Q000648:ultrastructure*; D046529:Microscopy, Electron, Transmission; D009130:Muscle, Smooth / Q000648:ultrastructure*; D012704:Serous Membrane / Q000166:cytology