Cellular mechanisms of ion transport associated with osmotic gradients in XXXX small intestine.

@entity35 @entity2656 @entity1372 @entity2865
1. The electrical potential difference, short-circuit current, tissue conductance, and fluxes of @entity1372 and @entity2865 were measured in @entity35 small intestine in an in vitro chamber preparation in the presence and absence of 100 mM- @entity2656 on either the mucosal or serosal surface. 2. Mucosal @entity2656 generally decreased potential difference, short-circuit current, and tissue conductance while serosal @entity2656 increased the electrical variables. 3. Mucosal @entity2656 decreased unidirectional movement of @entity1372 and @entity2865 but did not change the net transport of these ions. The change in short-circuit current was therefore ascribed to changes in fluxes of ions other than @entity1372 and @entity2865 . 4. Serosal @entity2656 increased the unidirectional fluxes of @entity1372 , but not the new transport of this ion. The transport of @entity2865 increased only in the serosal to mucosal direction yielding a net secretion of @entity2865 equal to the change in short-circuit current. 5. The changes in potential difference and short-circuit current caused by mucosal @entity2656 were dependent on the presence of @entity1372 . The changes due to serosal @entity2656 were dependent on both @entity1372 and @entity2865 . 6. Changes in undirectional transport of ions, small non-electrolytes, and water due to an osmotic gradient were attributed to changes in the dimension of the lateral intercellular spaces observed in earlier studies. 7. No evidence suggesting that the electrical changes due to the @entity2656 gradients could be attributed to diffusive or convective flows of fluid, but instead the changes were ascribed to perturbations in the cellular transport mechanisms.
