Peptidergic nerves in the colon of patients with ulcerative colitis

The cause of impaired motility, such as diarrhea and toxic megacolon, in patients with ulcerative colitis is unknown. Neuropeptides have recently been shown to be a neurotransmitter in the non-adrenergic non-cholinergic inhibitory and excitatory nerves in the human gut. To clarify the physiological significance of vasoactive intestinal polypeptide, substance P and neurotensin in the colon of patients with ulcerative colitis, we investigated the enteric nerve responses on lesional and normal bowel segments derived from patients with ulcerative colitis and patients who underwent colon resection for colonic cancers.

Twenty-four specimens were obtained from the lesional colon of 6 patients with ulcerative colitis (4 male, 2 female; ages 14-51 years, mean: 40.3 years). The patients with ulcerative colitis had chronic disease (4 with moderate disease, 2 with severe disease). Seventy-two specimens were obtained from the normal colon of 10 patients with colonic cancer (8 men and 2 women; ages 40-56 years, mean: 51.2 years). A mechanographic technique was used to evaluate in vitro muscle responses to these peptides of adrenergic and cholinergic nerves before and after treatment with various autonomic nerve blockers.

(1) Peptidergic nerves such as vasoactive intestinal polypeptide, substance P, and neurotensin nerves were found to act on both normal colon and ulcerative colitis colon; (2) the colon with ulcerative colitis was more strongly innervated by vasoactive intestinal polypeptide nerves than the normal colon; (3) Substance P and neurotensin nerves act more weakly in the UC colon that the normal colon.

These findings suggest that peptidergic nerves play an important role in the impaired motility observed in patients with UC.