Posible role of the enzimes carbonic anhydrase, and V-H+-ATPase, and the Cl-/HCO3- exchanger in electrogenic ion transport across the gills of the euryhaline crab Chasmagnathus granulatus.

GENOVESE, G.; ORTIZ, N.; URCOLA, M. R.; LUQUET, C. M.

Comparative Biochemistry and Physiology. A: Comparative Physiology

Elsevier

Lugar: Victoria; Año: 2005 vol. 142 p. 362 - 369

0300-9629

We studied the participation of carbonic anhydrase (CA), V?H+?ATPase, and Cl/HCO3 exchanger in electrogenic ion absorption throughthe gills of Chasmagnathus granulatus. CA activity was measured in anterior gills and posterior gills after acclimation to 2, 10, 30 (aboutseawater), and 45 salinity. The highest CA specific activity was detected in the microsomal fraction in anterior gills, and in the cytosolicfraction, in posterior ones. Both fractions were strongly induced by decreasing salinity only in posterior gills. Perfusion of posterior gills fromcrabs acclimated to either 2or 10 with acetazolamide inhibited CA activity almost completely. In posterior gills from crabs acclimated to 2and perfused with 20 saline (iso-osmotic for these crabs), acetazolamide reduced transepithelial potential difference (Vte) by 47%, furtheraddition of ouabain enhanced the effect to 88%. Acetazolamide had no effect in the same gills perfused with 30 saline (iso-osmotic for seawateracclimated crabs). Bafilomycin A1 and SITS (inhibitors of V?H+?ATPase and Cl/HCO3) reduced Vte by 15?16% in gills perfused with normal20 saline, and by 77% and 45%, respectively when they