An inwardly rectifying potassium channel in the basolateral membrane of sheep parotid secretory cells
| Autor: | D. I. Cook, E. A. Wegman, T. Ishikawa |
|---|---|
| Rok vydání: | 1993 |
| Předmět: |
medicine.medical_specialty
Potassium Channels Physiology Biophysics Cesium Membrane Potentials chemistry.chemical_compound Internal medicine medicine Extracellular Animals Parotid Gland Patch clamp Cells Cultured Epithelial polarity Sheep Tetraethylammonium Dose-Response Relationship Drug Inward-rectifier potassium ion channel Chemistry Conductance Cell Biology Tetraethylammonium Compounds Potassium channel Electrophysiology Endocrinology Potassium |
| Zdroj: | The Journal of Membrane Biology. 131:193-202 |
| ISSN: | 1432-1424 0022-2631 |
| DOI: | 10.1007/bf02260108 |
| Popis: | Using whole-cell patch-clamp techniques, we demonstrate that sheep parotid secretory cells have both inwardly and outwardly rectifying currents. The outwardly rectifying current, which is blocked by 10 mmol/liter tetraethylammonium (TEA) applied extracellularly, is probably carried by the 250 pS Ca(2+)- and voltage-activated K+ (BK) channel which has been described in previous studies. In contrast, the inwardly rectifying current, which is also carried by K+ ions, is not sensitive to TEA. It is similar to the inwardly rectifying currents observed in many excitable tissues in that (i) its conductance is dependent on the square root of the extracellular K+, (ii) the voltage range over which it is activated is influenced by the extracellular K+ concentration and (iii) it is blocked by the addition of Cs+ ions (670 mumol/liter) to the bathing solution. Our previously published cell-attached patch studies have shown that the channel type most commonly observed in the basolateral membrane of unstimulated sheep parotid secretory cells is a K+ channel with a conductance of 30 pS and, in this study, we find that its conductance also depends on the square root of the extracellular K+ concentration. It thus seems likely that it carries the inwardly rectifying K+ current seen in the whole-cell studies. |
| Databáze: | OpenAIRE |
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