Nitric oxide-containing nerves in bowel segments of patients with Hirschsprung's disease

To assess the role of nerves that synthesize nitric oxide (NO) in Hirschsprung's Disease (HD), the authors studied the distribution of the enzyme NADPH diaphorase (NADPHd) in normal and diseased bowel segments. In the proximal (ganglionic) segment of the colon, NADPHd-positive neurons were present in both myenteric and submucosal plexuses. In the distal involved colonic segments from HD patients, the typical pattern of the neuronal network was completely missing in the regions of the two plexuses; instead, only disorganized NADPHd-positive nerve fibers were present and NADPHd-reactive neurons were absent. Mucosal NO synthase activity was 2.76 ± 0.38 nmol/g/min in the proximal segment and only 0.83 ± 0.49 nmol/g/min in the distal segment ( P < .05, N = 3).