“…A depletion of ATP inhibits secretion of chloride ions to a greater extent in the distal portion of the colon of rats than in the proximal portion of the colon. 24 Similarly for our study, a gradual depletion of ATP in the Ussing chamber environment would reduce secretion of chloride ions in the mucosa of the descending colon, which would cause a lower electrical conductance, compared with the electrical resistance in the transverse colon. Alternately, greater transport of sodium ions in the mucosa of the descending colon, compared with transport in the transverse colon, could explain regional differences in electrical conductance that were detected in our study.…”