Effects of nicotine on intestinal epithelial cells in vivo and in vitro: an X-ray microanalytical study

It has been suggested that nicotine may have a beneficial effect on ulcerative colitis. Little is known, however, about the mechanism of such an effect. In the present study, the effects of nicotine on intestinal ion transport were investigated by X-ray microanalysis. In addition to an in vivo study, an in vitro system was established by pre-incubating pieces of small intestine in solutions of different ionic composition, in an attempt to stabilize the intracellular ionic composition. It was observed that nicotine caused a loss of Cl (indicative of net chloride efflux) in the villous epithelial cells and the cells of Brunner's glands, in vitro both in Na+ and in K+-containing medium. In in vivo experiments, exposure of mice for 10 days to nicotine in drinking water resulted in a lowering of the cellular chloride concentration in villous epithelial cells of the small intestine, cells of Brunner's glands and epithelial cells of the colon. The results may indicate a disturbance of fluid transport in the intestine by nicotine. Possible mechanisms, such as inhibition of uptake of chloride across the basolateral membrane, are discussed.