THE ROLE OF CAPSAICIN-SENSITIVE SENSORY NEURONS IN HEALING OF HCL-INDUCED GASTRIC-MUCOSAL LESIONS IN RATS

Background/Aims: Capsaicin-sensitive sensory neurons are important in protecting the stomach against damage. This study investigated the role of these sensory neurons in the healing of gastric lesions. Methods: Rats fasted for 18 hours were given 1 ml of 0.6N HCI orally for induction of gastric lesions; they were then fed normally from 1 hour later. On various days after HCI treatment, the area of lesion, acid secretion, mucosal DNA synthesis, mucosal H+ permeability, and blood flow responses were measured. Results: Ablation of sensory neurons by capsaicin pretreatment did not affect the development of gastric lesions in response to HCI but significantly delayed the healing of these lesions. The damaged mucosa secreted less acid and had minimal changes in DNA synthesis but showed a marked increase in H+ permeability, resulting in luminal acid loss accompanied by an increase of mucosal blood flow. Sensory deafferentation did not have any influence on such changes in the damaged stomach, except the mucosal hyperemic response to acid. Conclusions: Capsaicin-sensitive sensory neurons may contribute to the healing of gastric lesions by mediating the mucosal hyperemic responses associated with acid back-diffusion and by facilitating acid disposal in the mucosa. © 1994.