Interdependence of active Na+ and Cl− transport by the isolated urinary bladder of the teleost,Pseudopleuronectes americanus

摘要: The relationship between transepithelial Na+ and Cl- active transport from the mucosal toward serosal surface was studied by ion substitution experiments in isolated, perfused urinary bladder of winter flounder, Pseudopleuronectes americanus. tissue behaves as a simple ohmic resistance about 1000 ohm-cm2 which not significantly changed perfusion lumen (mucosal surface) with Na-free or Cl-free solutions. Trans-epithelial electrical potential difference short-circuit current were reversed (mucosa positive to negative) but unaltered medium. Short-circuit did agree isotopically measured net flux either control ion-substituted depressed more than 50% similar effect seen on upon perfusion. A kinetic analysis concentration perfusate presence absence Na+, respectively, indicated that medium acted non-competitive inhibitor transport, could be interpreted similarly. This inter-dependence taken an indication co-transport these two ions. Amiloride (10(-4) M) seemed inhibit component Na distinct Cl-dependent flux. It had no transport.