Ultracytochemical localization of Ca2+ ATPase activity in the inner ear of the guinea pig

摘要

In contrast to the perilymph, cochlear endolymph nshows the special ionic components of a high K+ and nlow Na+. Bosher et al reported that the cochlear enndolymph of laboratory rats contains very low Ca2+. Al-nthough the Ca2+concentration in the endolymph in very nlow in contrast to that of the extracellular fluids, it is nmuch higher than the Ca2+ level in the cytoplasm. Calncium is an important intracellular messenger and it has nbeen generally accepted that Ca2+ plays an important nrole in various cellular and enzyme functions.The low nCa2+ ions of endolymph are necessary for auditory and nvestibular functions. The purpose of our present study nwas to demonstrate this ultrastructural localization of nCa2+-ATPase activity in the cochlea for a better undernstanding of possible Ca2+ movement in the organ of Corti.