The inhibitory effect of reserpine on the active sodium transport across the frog bladder.

1. The effects of reserpine and harman derivatives on the sodium transport across the frog bladder were examined using a short-circuit current method. The effects of harman derivatives on the Na,K-ATPase activity of the frog kidney were also investigated. 2. Reserpine and harman derivatives inhibited active sodium transport of the frog bladder and their inhibitory effect decreased as reserpine greater than harmine greater than harmaline = harman greater than harmalol. 3. Harman derivatives inhibited Na,K-ATPase activity of the frog kidney. 4. These results suggest that reserpine and harman derivatives inhibit active sodium transport by suppressing the Na,K-ATPase activity of the frog bladder.