Abstract 222

Aim: Interstitial cells of Cajal (ICC) have recently been identified as intestinal pacemaker cells. This study examined with the help of confocal laser scanning microscopy (CLSM) the relationship between the myenteric plexus and ICC in different parts of the normal and Hirschsprung's disease (HD) bowel.

Material: Full thickness specimens of small and large bowel obtained at autopsy from 24 patients who died of non-gastrointestinal causes and from 8 patients with HD were examined using whole-mount immunohistochemistry and CLSM.

Results: Three-dimensional CLSM demonstrated two distinct neuronal networks in the bowel wall. (1.) ICC in the intermuscular layer with frequent projection of ICC cells in intramuscular fibres. (2.) Myenteric plexus. No significant difference in the ICC density relating to age or bowel site was identified. In the aganglionic part of HD there was marked reduction in the number of the ICC compared to ganglionic bowel. Interconnections were not found between these two networks.

Conclusions: The lack of communication between myenteric plexus and ICC suggests that these two major neuronal networks act independently in controlling intestinal function. The whole-mount technique may provide valuable information regarding these two neuronal networks in the investigation of intestinal motility disorders.