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Potassium Recycling Pathways in the Human Cochlea
Author(s) -
Weber Peter C.,
Cunningham Calhoun D.,
Schulte Bradley A.
Publication year - 2001
Publication title -
the laryngoscope
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.181
H-Index - 148
eISSN - 1531-4995
pISSN - 0023-852X
DOI - 10.1097/00005537-200107000-00006
Subject(s) - cochlea , spiral ligament , fibrocyte , spiral ganglion , inner ear , chemistry , endocochlear potential , microbiology and biotechnology , staining , epithelial polarity , anatomy , biophysics , biology , biochemistry , pathology , membrane , medicine , organ of corti
Abstract Objectives/Hypothesis Potential pathways for recycling potassium (K + ) used in the maintenance of inner ear electrochemical gradients have been elucidated in animal models. However, little is known about K + transport in the human cochlea. This study was designed to characterize putative K + recycling pathways in the human ear and to determine whether observations from animal models can be extrapolated to humans. Study Design A prospective laboratory study using an immunohistochemical approach to analyze the distribution of key ion transport mediators in the human cochlea. Methods Human temporal bones were fixed in situ within 1 to 6 hours of death and subsequently harvested at autopsy. Decalcification was accomplished with the aid of microwaving. Immunohistochemical staining was then performed to define the presence and cell type‐specific distribution of Na,K‐ATPase, sodium–potassium–chloride cotransporter (NKCC), and carbonic anhydrase (CA) in the inner ear. Results Staining patterns visualized in the human cochlea closely paralleled those seen in other species. Anti‐Na,K‐ATPase stained strongly the basolateral plasma membrane of strial marginal cells and nerve endings underlying hair cells. This antibody also localized Na,K‐ATPase to type II, type IV, and type V fibrocytes in the spiral ligament and in limbal fibrocytes. NKCC was present in the basolateral membrane of strial marginal cells as well as in type II, type V, and limbal fibrocytes. Immunoreactive carbonic anhydrase was present in type I and type III fibrocytes and in epithelial cells lining Reissner's membrane and the spiral prominence. Conclusions The distribution of several major ion transport proteins in the human cochlea is similar but not identical to that described in various rodent models. These results support the presence of a complex system for recycling and regulating K + homeostasis in the human cochlea, similar to that described in other mammalian species.