Regional and transmural density of interstitial cells of Cajal in human colon and rectum

The interstitial cells of Cajal (ICC) are thought to play an important role in the control of gut motility. The regional and transmural pattern of dis tribution of ICC in the normal human colon and rectum was evaluated with im munohistochemistry using an anti-c-hit antibody. The transmural distributio n of ICC was constant throughout the whole colon, the density of ICC was si gnificantly greater at the myenteric plexus than at either the longitudinal or circular muscle layers, and in the rectum the transmural distribution w as more even. Regionally, at the myenteric plexus, the transverse colon had a significantly greater density of ICC compared with the right colon (P = 0.038), left colon (P = 0.006), and rectum (P = 0.008). The pattern of dist ribution of ICC identified in this study is consistent with the proposed ro les of ICC as colorectal pacemakers, intermediaries of the neural control o f muscle activity, and coordinators of colorectal muscle activity. The high est density of ICC was at the myenteric plexus of the transverse colon, whi ch is the proposed region of pacemaking activity.