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Updated: Jul 29, 2026
11:52
Whole-cell Patch-clamp Recordings of Isolated Primary Epithelial Cells from the Epididymis
Published on: August 3, 2017
Basolateral K+ conductance establishes driving force for cation absorption by outer sulcus epithelial cells
1Cellular Biophysics Laboratory, Anatomy & Physiology Dept., Kansas State University, Manhattan, KS 66506, USA.
The Journal of Membrane Biology
|November 24, 2001
Summary
Outer sulcus epithelial cells actively absorb cations, crucial for hearing. Their basolateral membrane, rich in potassium channels and Na+,K+-ATPase, drives this cation transport, maintaining inner ear fluid balance.
Area of Science:
- Oto-rhino-laryngology
- Cell Physiology
- Ion Transport
Background:
- Outer sulcus epithelial cells actively reabsorb cations from cochlear endolymph.
- This reabsorption occurs via apical membrane nonselective cation channels.
- Understanding basolateral membrane transport is key to this process.
Purpose of the Study:
- To determine the transport properties of the basolateral membrane of outer sulcus epithelial cells.
- To elucidate the role of basolateral membrane ion channels in cation reabsorption.
- To investigate the contribution of these cells to endolymph homeostasis.
Main Methods:
- Whole-cell patch clamp technique was employed.
- Recordings focused on the basolateral membrane, minimizing apical membrane contribution.
- Ion concentration-response relationships and inhibitor effects were analyzed.
Main Results:
- Outer sulcus epithelial cells exhibit outward and inward currents with a resting potential near the K+ Nernst potential (-90.4 mV).
- A significant K+/Na+ permeability ratio (36) and voltage-independent K+ current were observed.
- This K+ current was inhibited by barium, amiloride, quinine, lidocaine, and ouabain.
Conclusions:
- The basolateral membrane possesses a large K+ conductance and Na+,K+-ATPase.
- This facilitates cation entry across the apical membrane, driving vectorial cation absorption.
- Outer sulcus cells contribute significantly to endolymph homeostasis through this mechanism.
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