Comparison of the intracellular membrane potentials in crystalline lenses of various frogs.

The intracellular membrane potentials were measured in the individual lens fibers of three kinds of frogs (Rana catesbeiana, Rana pipiens japonica, Rana nigromata) by a conventional glass microelectrode technique, in which the electrode was advanced to a depth of 200 micron from the anterior surface into the lens interior. The maximum intracellular membrane potentials obtained in both anterior and posterior sides of all preparations were between -90 and -95 mV. The measured potentials were nearly close to the EK, and the membrane potentials in in vitro experiments correlated well with in vivo measurements. Low membrane potentials reported previously in various frog lenses were discussed in comparison with the present results.