Role of slc26a3 Cl⁻/HCO₃⁻ exchanger for HCO₃⁻ secretion in the mouse large intestine

Abstract

A Cl⁻/HCO₃⁻ exchanger slc26a3 is expressed in the large intestine. To determine whether slc26a3 is involved in HCO₃⁻ secretion in the large intestine, we examined Cl⁻/HCO₃⁻ exchange activity of HEK293 cells transfected with mouse slc26a3 by microfluorometry using a pH-sensitive dye BCECF. The result showed that slc26a3 was largely inhibited by 0.1 mM glibenclamide while it was hardly inhibited by 30 &muM NPPB. In contrast, the Cl⁻-dependent bicarbonate secretion in the mouse large intestine (cecum) as determined by using pH-stat method was not inhibited by 0.1 mM glibenclamide while it was largely inhibited by 30 &muM NPPB. Therefore, slc26a3 may not play a major role in the Cl⁻-dependent bicarbonate secretion in the cecum. [J Physiol Sci. 2007;57 Suppl:S219]