[Contribution of cell culture to the study of cochlear endolymph]

Investigation of the mechanisms involved in the secretion of cochlear endolymph is hindered by the heterogeneity, the fragility, and the difficulty of access to the secretory structures of the inner ear, i.e. stria vascularis and Reissner's membrane. Cell culture may overcome these limitations and allow the study of the epithelial transport processes. Cultured cells derived from gerbil's explants of stria vascularis and Reissner's membrane presented morphological and immunohistochemical properties similar to those of the native cells. Investigation by the patch clamp technique of the apical membranes of marginal-like cells showed the presence of non specific cationic channels that could allow passive K+ flow towards endolymph and, thus, play a major role in the production of endolymph. Biochemical studies demonstrated that a cAMP production by these marginal-like cells. Primary culture of stria vascularis and Reissner's membrane is a suitable model to further investigate the physiology of endolymph production.