The Human Red Cell Voltage-regulated Cation Channel. The Interplay with the Chloride Conductance, the Ca 2+ -activated K + Channel and the Ca 2+ Pump
| Autor: | Poul Bennekou, Palle Christophersen, Berit I. Kristensen |
|---|---|
| Rok vydání: | 2003 |
| Předmět: |
Erythrocytes
Potassium Channels Physiology Biophysics Analytical chemistry Calcium-Transporting ATPases Chloride Ion Channels Feedback Membrane Potentials Potassium Channels Calcium-Activated Chloride Channels Extracellular medicine Homeostasis Humans Cells Cultured Membrane potential Calcium metabolism Dose-Response Relationship Drug Red Cell Chemistry Erythrocyte Membrane Electric Conductivity Time constant Conductance Cell Biology Intermediate-Conductance Calcium-Activated Potassium Channels Adaptation Physiological Potassium channel Nonlinear Dynamics Potassium Channels Voltage-Gated Potassium Calcium Ion Channel Gating medicine.drug |
| Zdroj: | Journal of Membrane Biology. 195:1-8 |
| ISSN: | 1432-1424 0022-2631 |
| DOI: | 10.1007/s00232-003-2036-6 |
| Popis: | The activation/deactivation kinetics of the human erythrocyte voltage-dependent cation channel was characterized at the single-channel level using inside-out patches. It was found that the time dependence for voltage activation after steps to positive membrane potentials was slow ( t(1/2) about 30 s), whereas the deactivation was fast ( t(1/2) about 15 ms). Both activation and deactivation of this channel were also demonstrated in intact red cells in suspension. At very positive membrane potentials generated by suspension in extracellular low Cl(-) concentrations, the cation conductance switched on with a time constant of about 2 min. Deactivation of the cation channel was clearly demonstrated during transient activation of the Gárdos channel elicited by Ca(2+) influx via the cation channel and ensuing efflux via the Ca(2+) pump. Thus, the voltage-dependent cation channel, the Gárdos channel and the Ca(2+) pump constitute a coupled feedback-regulated system that may become operative under physiological conditions. |
| Databáze: | OpenAIRE |
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