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08:08
Monitoring the Effect of Osmotic Stress on Secretory Vesicles and Exocytosis
Published on: February 19, 2018
Physiological significance of hypotonicity-induced regulatory volume decrease: reduction in intracellular Cl-
Hiroaki Miyazaki1, Atsushi Shiozaki, Naomi Niisato
1Departments of Molecular Cell Physiology, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan.
American Journal of Physiology. Renal Physiology
|January 25, 2007
Summary
Regulatory volume decrease (RVD) reduces intracellular chloride concentration ([Cl(-)](i)) in kidney cells. This chloride reduction acts as a signal to regulate cellular functions during cell volume regulation.
Area of Science:
- Cell Biology
- Renal Physiology
- Ion Transport
Background:
- Regulatory volume decrease (RVD) is a cellular response to hypotonic stress, involving ion and water effluxes.
- Previous studies suggested RVD influences Na+ reabsorption by altering intracellular chloride ([Cl(-)](i)) but direct measurement was challenging.
Purpose of the Study:
- To develop and utilize a novel method for accurately measuring intracellular chloride concentration ([Cl(-)](i)) changes during RVD.
- To elucidate the role of [Cl(-)](i) reduction as a physiological signal in RVD.
Main Methods:
- Development of a high-resolution flow cytometry method using a halide-specific fluorescent dye (N-(6-methoxyquinolyl) acetoethyl ester).
- Measurement of [Cl(-)](i) in A6 renal cells under isotonic and hypotonic conditions.
- Assessment of [Cl(-)](i) changes with and without RVD inhibition using NPPB (Cl- channel blocker) and quinine (K+ channel blocker).
Main Results:
- A6 cells exhibited a significant decrease in [Cl(-)](i) from 43.6 mM to 10.8 mM during RVD following hypotonic shock.
- Inhibition of RVD by NPPB or quinine prevented the reduction of [Cl(-)](i).
- The observed [Cl(-)](i) reduction was directly linked to the RVD process.
Conclusions:
- Regulatory volume decrease (RVD) significantly reduces intracellular chloride concentration ([Cl(-)](i)) in renal epithelial cells.
- The reduction of [Cl(-)](i) during RVD serves as a crucial intracellular signal regulating cellular functions.
- This study provides a new method for measuring intracellular halide concentrations during dynamic cellular processes.
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