Short chain fatty acids but not lactate or succinate stimulate mucus release in the rat colon

Background: Short chain fatty acids (SCFAs) affect various intestinal functions. Mucus is an important physiological component of the intestinal mucosal barrier. However, the effect of SCFAs or other organic acids on the intestinal mucus release is poorly understood. The aim of this study was to investigate whether lumen SCFA stimulates mucus release into the rat colon. Methods: A solution of SCFA, lactate or succinate was infused into the colon of anesthetized rats, and we then measured the hexose content of the effluent. We also examined the influence of cholinergic antagonists on the effects of SCFA. Results: A SCFA mixture (75 mM acetate, 35 mM propionate and 20 mM butyrate) or individual SCFAs (130 mM) increased the mucus release into the colon in a similar manner. The individual SCFAs, but not lactate or succinate, stimulated colonic mucus secretion in similar concentration-dependent manners. Butyrate stimulated colonic mucus secretion at 20 mM, but acetate, propionate, lactate and succinate at this concentration did not. Pretreatment with an anti-cholinergic agent diminished the stimulatory effects of SCFAs on mucus secretion. Conclusions: Lumen SCFAs, but not lactate or succinate, stimulate mucus release from the rat colon via a cholinergic nerve mechanism.