Possible role of carbonic anhydrase, V–H+–ATPase, and 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-MOLECULAR AND INTEGRATIVE PHYSIOLOGY

Elsevier

Año: 2005 vol. 142 p. 362 - 369

1095-6433

We studied the participation of carbonic anhydrase (CA), V–H+–ATPase, and Cl/HCO3 exchanger in electrogenic ion absorption through the gills of Chasmagnathus granulatus. CA activity was measured in anterior gills and posterior gills after acclimation to 2, 10, 30 (about seawater), and 45 salinity. The highest CA specific activity was detected in the microsomal fraction in anterior gills, and in the cytosolic fraction, in posterior ones. Both fractions were strongly induced by decreasing salinity only in posterior gills. Perfusion of posterior gills from crabs acclimated to either 2or 10 with acetazolamide inhibited CA activity almost completely. In posterior gills from crabs acclimated to 2+–ATPase, and Cl/HCO3 exchanger in electrogenic ion absorption through the gills of Chasmagnathus granulatus. CA activity was measured in anterior gills and posterior gills after acclimation to 2, 10, 30 (about seawater), and 45 salinity. The highest CA specific activity was detected in the microsomal fraction in anterior gills, and in the cytosolic fraction, in posterior ones. Both fractions were strongly induced by decreasing salinity only in posterior gills. Perfusion of posterior gills from crabs acclimated to either 2or 10 with acetazolamide inhibited CA activity almost completely. In posterior gills from crabs acclimated to 2Chasmagnathus granulatus. CA activity was measured in anterior gills and posterior gills after acclimation to 2, 10, 30 (about seawater), and 45 salinity. The highest CA specific activity was detected in the microsomal fraction in anterior gills, and in the cytosolic fraction, in posterior ones. Both fractions were strongly induced by decreasing salinity only in posterior gills. Perfusion of posterior gills from crabs acclimated to either 2or 10 with acetazolamide inhibited CA activity almost completely. In posterior gills from crabs acclimated to 2 salinity. The highest CA specific activity was detected in the microsomal fraction in anterior gills, and in the cytosolic fraction, in posterior ones. Both fractions were strongly induced by decreasing salinity only in posterior gills. Perfusion of posterior gills from crabs acclimated to either 2or 10 with acetazolamide inhibited CA activity almost completely. In posterior gills from crabs acclimated to 2or 10 with acetazolamide inhibited CA activity almost completely. In posterior gills from crabs acclimated to 2 and perfused with 20 saline (iso-osmotic for these crabs), acetazolamide reduced transepithelial potential difference (Vte) by 47%, further addition of ouabain enhanced the effect to 88%. Acetazolamide had no effect in the same gills perfused with 30 saline (iso-osmotic for seawater acclimated crabs). Bafilomycin A1 and SITS (inhibitors of V–H+–ATPase and Cl/HCO3) reduced Vte by 15–16% in gills perfused with normal 20 saline, and by 77% and 45%, respectively when they were applied in Na-free 20 saline, suggesting the participation of those transporters and cytosolic CA in electrogenic ion absorption. saline (iso-osmotic for these crabs), acetazolamide reduced transepithelial potential difference (Vte) by 47%, further addition of ouabain enhanced the effect to 88%. Acetazolamide had no effect in the same gills perfused with 30 saline (iso-osmotic for seawater acclimated crabs). Bafilomycin A1 and SITS (inhibitors of V–H+–ATPase and Cl/HCO3) reduced Vte by 15–16% in gills perfused with normal 20 saline, and by 77% and 45%, respectively when they were applied in Na-free 20 saline, suggesting the participation of those transporters and cytosolic CA in electrogenic ion absorption. saline (iso-osmotic for seawater acclimated crabs). Bafilomycin A1 and SITS (inhibitors of V–H+–ATPase and Cl/HCO3) reduced Vte by 15–16% in gills perfused with normal 20 saline, and by 77% and 45%, respectively when they were applied in Na-free 20 saline, suggesting the participation of those transporters and cytosolic CA in electrogenic ion absorption.1 and SITS (inhibitors of V–H+–ATPase and Cl/HCO3) reduced Vte by 15–16% in gills perfused with normal 20 saline, and by 77% and 45%, respectively when they were applied in Na-free 20 saline, suggesting the participation of those transporters and cytosolic CA in electrogenic ion absorption. saline, and by 77% and 45%, respectively when they were applied in Na-free 20 saline, suggesting the participation of those transporters and cytosolic CA in electrogenic ion absorption.