Comparison of ion transport mechanisms between vestibular dark cells and strial marginal cells

Morphologic similarities between strial marginal cells and vestibular dark cells have long been recognized and it has long been accepted that both of these cell types are involved in the secretion of K+ into endolymph. Functional similarities of these two epithelia however, were considered unlikely as long as strial marginal cells were assumed to generate the endocochlear potential which has no equivalent in the vestibular labyrinth. The recently introduced concept that strial marginal cells transport K+ but that the mechanism for the generation of the endocochlear potential is located in another cell type provided the basis to hypothesize that ion transport mechanisms and their regulation are similar in vestibular dark and strial marginal cells. The present review compiles evidence in support of this hypothesis.