ROLE OF SENSORY AFFERENT NEURONS IN HYPERTONIC DAMAGE AND RESTITUTIONOF THE RAT GASTRIC-MUCOSA

Background & Aims: Gastric mucosal hyperemia is a protective response mediated at least in part by the response of sensory afferent neurons to hydrogen ions, The aim of this study was to determine if other path ways to the hyperemic response are present and if these neurons have a n effect exclusive of hyperemia on mucosal protection and repair. Meth ods: Rat sensory afferent: neurons were ablated by capsaicin treatment , Chambered stomachs were damaged by hypertonic saline followed by eit her acidic or neutral isotonic saline, Blood flow was measured by lase r Doppler velocimetry, and mucosal morphology was quantitatively evalu ated by microscopy. Results: Mucosal damage alone evoked a strong hype remic response in both control and ablated rats. Ablated rats lost gas tric protection despite this hyperemic response. Acid exposure after d amage sustained the hyperemic response, Rapid epithelial restitution o ccurred faster (even over hemorrhagic lesions) in control rats, Conclu sions: The hyperemic response to mucosal damage alone is not mediated by sensory neurons. Protection of the stomach by sensory afferent neur ons occurs by mechanisms also unrelated to their elicitation of hypere mia. Restitution during acid challenge is enhanced by the sustained hy peremic response mediated through sensory afferent neurons.