A proton pump contributes to neuroblastoma x glioma cell membrane potentials
| Autor: | Jean-Marc Dubois, Béatrice Rouzaire-Dubois |
|---|---|
| Rok vydání: | 1997 |
| Předmět: |
Membrane potential
Patch-Clamp Techniques Tetraethylammonium Physiology Chemistry Cell Membrane Clinical Biochemistry Electric Conductivity Pipette Analytical chemistry Glioma Hybrid Cells Proton Pumps Hyperpolarization (biology) Membrane Potentials Neuroblastoma chemistry.chemical_compound Physiology (medical) Tumor Cells Cultured Repolarization Channel blocker Patch clamp Na+/K+-ATPase |
| Zdroj: | Pfl�gers Archiv European Journal of Physiology. 434:750-755 |
| ISSN: | 1432-2013 0031-6768 |
| DOI: | 10.1007/s004240050461 |
| Popis: | The contribution of an electrogenic proton pump to the membrane potential of neuroblastoma x glioma hybrid NG 108-15 cells was determined with whole-cell voltage and current recordings and cell volume measurements with the preparation bathed in symmetrical 140 mM KCl solutions. The effects of the K+ channel blockers tetraethylammonium and 4-aminopyridine and of the H+-ATPase inhibitor bafilomycin A1 on the membrane potential and input resistance revealed that the membrane potential is generated by an outward H+ pump current of 5-15 pA in equilibrium with an inward passive current. This conclusion is supported by both current- and voltage-clamp results obtained when the preparation was bathed in a Na+-containing external solution after K+ channel blockade with Cs+ in the pipette. Additional support was obtained by measurement of the volume of cells incubated in solutions containing 140 mM KCl. Tetraethylammonium induced a bafilomycin-sensitive increase in inward K+ current and an increase in cell volume of 76% which we believe to be a consequence of the K+ influx. Finally, comparison of membrane potentials obtained in experiments using Na+-containing external, and K+-containing pipette solutions and after K+ channel blockade with Cs+ in the pipette also showed that, under normal physiological conditions, the resting membrane potential is essentially determined by an electrogenic H+ pump. |
| Databáze: | OpenAIRE |
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