Electrolyte transport across the mouse small intestine.

Abstract

SummaryThe electrical and electrolyte transport properties of nonstripped mouse intestine were investigated using the Ussing chamber technique. In HCO3-NaCl 0Ringer solution a PD of 1.47 ± 0.17 mV and Ise, of 15.8 ± 1.56 μA existed across the intestine, orientated such that the serosa was electropositive to the mucosa. Radioisotope flux measurements demonstrated net Na absorption and Cl secretion. The Ise was less than the sum of net Na and Cl fluxes (JnetNa + Jnetcl), yielding a negative net residual flux (JnetR), indication of a simultaneous anion absorption or cation secretion. Glucose augmented JnetNa + Jnetcl and increased the PD and Isc. In the absence of bicarbonate, the JnetNa and JnetR were reduced to practically zero, suggesting that either HCO3- absorption or H+ secretion is responsible for the residual flux observed in HCO3- Ringer. These findings also indicate that Na absorption is HCO3- dependent.