Abstract
The macula sacculi in the mudpuppy is an inner ear sensory area accessible for intracellular recordings in vitro and in vivo. The resting potentials recorded in vitro can be explained by the electrodiffusion theory assuming a uniform ionic selectivity in the membranes of the neuroepithelial cells. The resting potentials recorded in vivo are significantly larger than predicted by the electrodiffusion theory, probably because of an electrogenic metabolic process present in the neuroepithelial cells. An equivalent circuit is proposed to explain the resting electrogenesis in the neuroepithelial cells present in the sensory area.