LOCALIZATION OF CARBONIC-ANHYDRASE IN THE SALIVARY-GLANDS OF THE COCKROACH, PERIPLANETA-AMERICANA

Carbonic anhydrase (CA) activity was localized in the salivery glands of the cockroach, Periplaneta americana, by (1) Hansson's histochemica l technique, and (2) the use of the fluorescent sulphonamide, 5-dimeth yl-amino-naphthalene-1-sulphonamide (DNSA). Both techniques reveal the same distribution pattern of CA in the four morphologically different cell types of the glands: peripheral cells, central cells, inner acin ar duct cells, and distal duct cells. Positive reactions with Hansson' s cobalt/phosphate technique were found in the apical regions of the p eripheral cells and the distal duct cells, and were inhibited by 10(-5 ) M acetazolamide in control experiments. No staining could be detecte d in the central cells and the inner acinar duct cells. The fluorescen t CA inhibitor DNSA (10(-4) M) specifically stained the peripheral cel ls and the distal duct cells in methanol-fixed cryostat sections, wher eas the central cells and the inner acinar duct cells remained unstain ed. The role of CA in the peripheral cells is not clear. CA activity i n the distal duct cells may provide the protons needed to run the vacu olar-type H+-ATPase on the apical infoldings of the cells. This ATPase may be involved in modification of the primary saliva.