Na+ and Cl− movement across the intestinal epithelium occurs by several interconnected
mechanisms:(a) nutrient-coupled Na+ absorption,(b) electroneutral NaCl absorption,(c)
electrogenic Cl− secretion by CFTR, and (d) electrogenic Na+ absorption by ENaC. All these
transport modes require a favorable electrochemical gradient maintained by the basolateral
Na+/K+-ATPase, a Cl− channel, and K+ channels. Electroneutral NaCl absorption is
observed from the small intestine to the distal colon. This transport is mediated by apical …