Influence of lithium upon the intracellular potential of frog skin epithelium.

The effect of Li upon the intracellular potential of frog skin (Rana esculenta) was investigated. In the range between 1 and 25 mM Li in the epithelial bathing solution, a semilogarithmic linear relationship between [Li] and intracellular potential under short circuit conditions was obtained. The intracellular potential at all [Li] is quantitatively sufficient to explain the previously reported accumulation of Li in the intracellular space of the frog skin epithelium (Leblanc, G. 1972. Pfluegers Arch. 337:1) on the basis of a passibe entrance step at the outer border. A reduction of the intracellular potential by Li is also observed in the presence of 6 mM Na in the epithelial bathing solution. Consequences regarding the mechanism of uptake of Na across the outer border of the frog skin are discussed.