Effect of Bicarbonate on Chloride-Dependent Transmural Potential and ATPase Activity in the Rectal Wall of Schistocerca gregaria

Abstract

An activating effect of bicarbonate on the active transport of CI~ across the rectal wall of Schistocerca gregaria has been found, as revealed by an increase of the transmural potential and short-circuit current. Acetazolamide, an inhibitor of both parameters, does not show this inhibitory effect, even at much higher concentrations, when added in the presence of bicarbonate. A Cl" or SO4~ anion dependent ATPase, different from the Na+, K+ ATPase, has also been found, which can be further stimulated by bicarbonate.