Role of capsaicin-sensitive nerves in gastric and hepatic injury induced by cold-restraint stress

The role of capsaicin-sensitive afferent fibers on cold-restraint stress-in duced gastric and hepatic injury was examined at the macroscopic and ultras tructural levels. Wistar albino rats were treated with capsaicin either loc ally (intragastric, perivagal, and periceliac) or systemically (neonatal, i ntraperitoneal). Perineural and neonatal treatment with capsaicin was used to denervate afferent fibers, while intragastric capsaicin treatment would have activated mucosal afferent fibers just before the stress exposure. Cap saicin decreased significantly the formation of macroscopic gastric lesions caused by stress in all treatment groups. At the electron microscopic leve l, however, denervation of vagal afferent fibers with capsaicin was most ef fective in prevention of cellular injury in gastric mucosa. In the liver, s ystemic denervation of afferent fibers completely inhibited stress-induced cellular damage, while denervation of afferentt fibers in vagus and splanch nic nerve was partially effective. Central neural pathways sensitive to cap saicin may mediate formation of both gastric and hepatic injury resulting f rom stress.