Chloride transport through the n onshort-circuited isolated skin of Rana esculenta.

The effects of acetazolamide (Diamox), ouabain, and amiloride on chloride movements through the isolated, nonshort-circuited Rana esculenta skin were investigated at different external NaCl concentrations. From hyposmotic solutions of low NaCl concentration (2 mM), two principal components of the chloride uptake may be distinguished: one dependent on the osmotic water flux and the other inhibited by Diamox but not by ouabain, amiloride, or removal of sodium from the external solution. Chloride uptake from a Ringer solution is always inhibited when either the sodium transport is blocked with amiloride or ouabain or when sodium is absent from the external solution. It can be concluded that the predominant component of the chloride transport mechanism when the external solution is concentrated (Ringer) is a sodium-dependent one. When chloride is absorbed from a solution of low concentration, however, a component predominated which is independent of sodium transport. It is suggested that the latter mechanism should be capable of exchanging chloride against endogenous base as in the in vivo skin.