Involvement of capsaicin-sensitive sensory neurons in stress-induced gastroduodenal mucosal injury in rats

The pathogenesis of stress-induced gastroduodenal mucosal injury is complex and incompletely understood. The aim of this investigation was to examine the involvement of gastric and duodenal capsaicin-sensitive neurons in muco sal damage associated with water-restraint stress (WRS) in rats. Following WRS, gastroduodenal mucosal injury was quantitated by macroscopic and micro scopic methods. Calcitonin gene-related peptide (CGRP) content was measured by radioimmunoassay. WRS-induced mucosal erosive injury in the stomach and duodenum (40.9 +/- 4.2 and 5.1 +/- 0.6 mm(2), respectively) was reduced si gnificantly (by 88% and 67%, respectively) by acute intragastric capsaicin administration prior to WRS. In contrast. sensory denervation by chronic ca psaicin significantly increased the area of gastric injury and duodenal dam age. WRS alone caused a significant reduction (by 52% and -35%, respectivel y) in gastric and duodenal CGRP content, which was prevented by acute capsa icin treatment. The data suggest that gastric and duodenal sensory neurons and CGRP are involved in the pathogenesis of stress-induced mucosal injury to the stomach and duodenum.