Three-dimensional structures of c-Kit-positive cellular networks in the guinea pig small intestine and colon

Cryosections and whole-mount preparations of the guinea pig small intestine and colon were single or double immunolabeled using the anti-c-Kit and pro tein gene product 9.5 antibodies. Immunolabeled specimens were observed und er a confocal laser scanning microscope. The main findings of the present s tudy are: (1) the distribution and profiles of three-dimensional structures of c-Kit-positive cellular networks in the small intestine and colon, and (2) the anatomical relations of c-Kit-positive cells to the enteric nerves in the layers. In the small intestine, c-Kit-positive cellular networks wer e observed at levels of the deep muscular plexus and myenteric plexus. The c-Kit-positive cellular networks ran along or overlay the nerve fibers at t he deep muscular plexus, while they showed the reticular structures intermi ngled with the nerve elements at the myenteric plexus. In the colon, c-Kit- positive cellular networks were observed at levels of the submuscular plexu s and myenteric plexus, and were further identified within the circular and longitudinal muscle layers as well as in the subserosal layer. In the circ ular muscle layer, c-Kit-positive cells surrounded the associated nerve fib ers and extended several long processes toward the adjacent c-Kit-positive cells. The c-Kit-positive cellular networks within the longitudinal muscle layer as well as in the subserosal layer were not associated with the nerve fibers. In the layers of the intestinal wall with c-Kit-positive cells, th e cellular networks of the interstitial cells were identified in ultrastruc ture. The characteristic profiles of c-Kit-positive cellular networks provi de a morphological basis upon which to investigate the mechanisms regulatin g intestinal movement.