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Sodium/proton exchange in mouse neuroblastoma cells
The Journal of Biological Chemistry
|December 25, 1981
Summary
Mouse neuroblastoma cells exhibit a rapid, transient H+ release upon sodium (Na+) addition, indicating a Na+/H+ exchange system. This system regulates intracellular pH and is inhibited by amiloride.
Area of Science:
- Cellular physiology
- Biochemistry
- Neuroscience
Background:
- Intracellular pH regulation is crucial for cell function.
- Neuroblastoma cells are a model for studying ion transport mechanisms.
Purpose of the Study:
- To investigate the mechanism of rapid proton (H+) release in mouse neuroblastoma cells upon sodium (Na+) addition.
- To characterize the properties of the Na+-dependent ion transport system.
Main Methods:
- Studied H+ flux in neuroblastoma cells using pH measurements.
- Investigated ion substitution effects (Li+, choline, K+, Ca2+).
- Assessed ATP independence, saturation kinetics, and membrane potential effects.
Main Results:
- Sudden Na+ addition caused transient H+ extrusion, increasing intracellular pH.
- Lithium (Li+) mimicked Na+, but other ions did not.
- The process was independent of ATP and membrane potential, saturating at 40 mM Na+.
- Amiloride completely inhibited Na+-dependent proton transport and Na+ uptake.
Conclusions:
- Neuroblastoma cells possess an electroneutral Na+/H+ exchange system in the plasma membrane.
- This system plays a significant role in regulating intracellular pH.
- The Na+/H+ exchanger is a potential target for therapeutic intervention.