Contraction of villi and fluid transport in dog jejunal mucosa in vitro.

LEE, J, S. Contraction of villi and fluid transport in dog jejunal mucosa in vitro. Am. J. Physiol. 221(2) : 488-495. 1971.-An intestinal mucosal membrane preparation permitting simultaneous determination of the fluid transport rate and a microscopic examination of villi was employed. The occurrence of sustained villus shortening was invariably associated with diminution or abolition of fluid transport. Villi contracted in this manner in Na-, K-, or glucose-free Ringer solution, in the presence of atropine sulfate, ouabain, phloridzin, 2,4-dinitrophenol or NaCN, in hypertonic Ringer solution, or at low temperature. In the villi with vigorous contraction, epithelial sloughing always occurred. In Caand HC03-free Ringer, the fluid transport rate decreased without shortening of villi, but in the Ca-free fluid some structural deterioration was noted. Within a wide range of pH (6/l-8.2), there was neither change in the fluid transport rate nor contraction of villi. It is considered that the sustained contraction of villi per se may inhibit fluid transport and that glucose, Na, K, or Ca apparently plays a role in preventing contraction and maintaining the structural integrity of the villi necessary for a normal rate of fluid transport.