Impedance of membrane and myoplasm during the action potential of frog muscle.

The transient imbalance of a Wheatstone bridge was used to estimate the changes in both membrane and myoplasmic impedance that occurred as an action potential propagated over a 1 mm length of a frog muscle fiber. It was also used to estimate the changes in the membrane impedance alone. Alterations in myoplasmic impedance that might have been predicted were not found.