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A Proteoliposome-Based Efflux Assay to Determine Single-molecule Properties of Cl- Channels and Transporters
Published on: April 20, 2015
KCl cotransport: a mechanism for basolateral chloride exit in Necturus gallbladder
The Journal of Membrane Biology
|January 1, 1983
Summary
Changes in external potassium (K+) concentration affect intracellular chloride (Cl-) activity in Necturus gallbladder epithelial cells. The study found that Cl- exit is driven by the K+ gradient across the basolateral membrane, suggesting a role for KCl transport.
Area of Science:
- Cellular Physiology
- Epithelial Transport
- Ion Homeostasis
Background:
- Understanding ion transport in epithelial cells is crucial for comprehending physiological processes.
- Intracellular chloride activity (aiCl) is a key parameter in regulating cell function and fluid balance.
Purpose of the Study:
- To investigate the influence of external potassium (K+) concentration on intracellular chloride activity (aiCl) in Necturus gallbladder epithelial cells.
- To elucidate the specific membrane (apical or basolateral) and driving force (chemical potential or membrane potential) involved in chloride transport.
Main Methods:
- Utilized K+- and Cl--selective double-barreled microelectrodes for precise measurements.
- Manipulated external K+ concentrations in apical and basolateral solutions to observe effects on aiCl.
- Analyzed the relationship between aiCl, chemical potential gradient for K+ (delta microK), and membrane potential.
Main Results:
- Decreased external K+ concentration led to a reduction in aiCl.
- Steady-state aiCl values correlated with delta microK across the basolateral membrane.
- aiCl showed minimal dependence on membrane potential, indicating low passive Cl- permeability through both apical and basolateral membranes.
Conclusions:
- Chloride (Cl-) exit from Necturus gallbladder cells is primarily driven by the chemical potential gradient for K+ (delta microK) across the basolateral membrane.
- Electroneutral KCl cotransport in the basolateral membrane is suggested to be a significant mechanism for transcellular Cl- transport.
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