IMPLICATION OF SENSORY NEURONS IN THE DIVERSE MECHANISMS OF ADAPTIVE CYTOPROTECTION IN THE RAT STOMACH

Adaptive cytoprotection is mediated by diverse mediators and mechanism s. We investigated the implication of capsaicin-sensitive afferent neu rons in the adaptive cytoprotection in the rat stomach, taking special notice of nitric oxide, prostaglandins and luminal dilution. Sensory deafferentation abolished the protective effect of capsaicin against 0 .6 N HCl-induced gastric injury but not the indomethacin-resistant or N-G-nitro-L-arginine-resistant adaptive cytoprotection conferred by 0. 1 N NaOH. Nor did it attenuate the protection by 0.35 N HCl which acco mpanied luminal dilution. These findings suggest that certain mild irr itants do not require sensory neurons to provide nitric oxide- and pro staglandins-mediated adaptive cytoprotection and, furthermore, that ca psaicin-sensitive afferent neurons are not crucial, either, so long as there is a contribution of luminal dilution in the adaptive cytoprote ction.