[Transmembrane exchange of C1- and HCO3- in erythrocytes: direct action of carbonic anhydrase inhibitors on the transport mechanism].

The only currently recognised role of unsubstituted sulphonamides is their specific inhibition of carbonic anhydrase. The results presented here show that they inhibit the HCO3/Cl- and Cl-/Cl- exchanges across the membrane of the ox erythrocyte. Carbonic anhydrase is not involved in this inhibition which is the result of a direct and specific action on the anion transfer mechanism at membrane level. This newly-recognised role of sulphonamides satisfactorily explains and integrates many experimental results concerning secretory tissues and the interpretation of the action of diuretics.