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Electrical properties of Ehrlich ascites tumor cells
Pflugers Archiv : European Journal of Physiology
|May 1, 1987
Summary
The cell membrane potential of Ehrlich ascites tumor cells is primarily driven by potassium diffusion, with minor contributions from sodium and chloride conductances. This finding is crucial for understanding cell electrophysiology in mammalian epithelial cells.
Area of Science:
- Cell Biology
- Biophysics
- Physiology
Background:
- Cell membrane potential (PD) is a critical parameter influencing cellular functions.
- Ehrlich ascites tumor cells serve as a model for studying mammalian epithelial cell electrophysiology.
Purpose of the Study:
- To investigate the primary determinants of cell membrane potential in Ehrlich ascites tumor cells.
- To quantify the contribution of different ions (potassium, sodium, chloride) to the membrane potential.
Main Methods:
- Continuous measurement of cell membrane potential using microelectrodes at 37°C.
- Rapid alterations of extracellular fluid composition to assess ionic effects.
- Application of specific ion concentrations (potassium, sodium, chloride) and inhibitors (barium, amiloride).
Main Results:
- The resting membrane potential was -56.7 ± 0.7 mV, with an apparent membrane resistance of 62.2 ± 2.2 MΩ.
- Increased extracellular potassium depolarized the membrane, indicating a significant potassium transference number (tk = 0.53 ± 0.01).
- Barium abolished apparent potassium conductance, while sodium and chloride reductions caused minor depolarizations and hyperpolarizations, respectively.
Conclusions:
- Cell membrane potential in Ehrlich ascites tumor cells is mainly generated by potassium diffusion.
- Sodium and chloride conductances play a relatively small role in establishing the membrane potential.
- The findings align with the electrophysiological characteristics of other mammalian epithelial cells.