Expression of Na/K-ATPase subunits in the human cochlea: a confocal and super-resolution microscopy study with special reference to auditory nerve excitation and cochlear implantation.

ABSTRACT: Background: For the first time the expression of the ion transport protein sodium/potassium-ATPase and its isoforms was analyzed in the human cochlea using light- and confocal microscopy as well as super-resolution structured illumination microscopy. It may increase our understanding of its role in the propagation and processing of action potentials in the human auditory nerve and how electric nerve responses are elicited from auditory prostheses. Material and methods: Archival human cochlear sections were obtained from trans-cochlear surgeries. Antibodies against the Na/K-ATPase ?1 isoform together with ?1 and ?3 were used for immunohistochemistry. An algorithm was applied to assess the expression in various domains. Results: Na/K ATPase ?1 subunit was expressed, mostly combined with the ?1 isoform. Neurons expressed the ?1 subunit combined with ?3, while satellite glial cells expressed the ?1 isoform without recognized association with ?1. Types I and II spiral ganglion neurons and efferent fibers expressed the Na/K-ATPase ?3 subunit. Inner hair cells, nerve fibers underneath, and efferent and afferent fibers in the organ of Corti also expressed ?1. The highest activity of Na/K-ATPase ?1 was at the inner hair cell/nerve junction and spiral prominence. Conclusion: The human auditory nerve displays distinct morphologic features represented in its molecular expression. It was found that electric signals generated via hair cells may not go uninterrupted across the spiral ganglion, but are locally processed. This may be related to particular filtering properties in the human acoustic pathway.

SUBMITTER: Liu W 

PROVIDER: S-EPMC6758701 | biostudies-literature | 2019 Aug

REPOSITORIES: biostudies-literature