Effects of menadione on active sodium transport in isolated frog skin

¹ Department of Biology, University of Oregon, Eugene, Oregon

The effects of menadione (2-methyl-1, 4-naphthoquinone), a potent inhibitor of choline acetylase, were studied. It was found that a 4 x 10^–5 m solution of the inhibitor causes a transient increase in short-circuit current and trans-skin potential followed by an exponential decrease in both variables. This pattern is observed on application of the inhibitor to either epidermal or dermal surface. Epidermal treatments are more effective as judged by the lag time of the decay phase.