Involvement of capsaicin-sensitive mechanism(s) in the antiulcer defence of intestinal mucosa in rats.

Capsaicin desensitization increases degree and incidence of indomethacin-induced intestinal ulcers in rats, suggesting the existence of a capsaicin-sensitive mechanism(s) in the protection of the intestinal mucosa against indomethacin-induced ulceration. Sensory innervation thus may be involved in the pathogenesis of ulcers of the small bowel, as well as in gastric ulcers. Administration of exogenous CGRP and somatostatin, sensory neuropeptides which are depleted by capsaicin desensitization, does not afford protection toward the capsaicin-induced aggravation of intestinal ulcers. The protective effect of exogenous prostaglandins toward indomethacin-induced intestinal ulceration is not mediated by capsaicin-sensitive nerve fibers.