Ca(2+)-dependent and Ca(2+)-permeable ion channels in aortic endothelial cells
| Autor: | W. C. O'Neill, B. N. Ling |
|---|---|
| Rok vydání: | 1992 |
| Předmět: |
Potassium Channels
Physiology chemistry.chemical_element Calcium Bradykinin Ion Channels Permeability Physiology (medical) Animals Patch clamp Ion channel Ion transporter Aorta Cells Cultured Chemistry Depolarization Anatomy Membrane hyperpolarization Hyperpolarization (biology) Electrophysiology Hypotonic Solutions Biophysics Potassium Cattle Endothelium Vascular Cardiology and Cardiovascular Medicine |
| Zdroj: | The American journal of physiology. 263(6 Pt 2) |
| ISSN: | 0002-9513 |
| Popis: | We investigated whether osmotic stress would activate specific ion channels in bovine aortic endothelial cells (BAECs). In isotonic medium (290 mosmol/kgH2O), cell-attached patch recordings contained both 165-pS K+ channels activated by depolarization and 40-pS K+ channels activated by 200 nM bradykinin. These inwardly rectifying K+ channels were activated by raising “cytoplasmic” Ca2+ in inside-out patches. BAEC exposed to hypotonic bath (220 mosmol/kg) exhibited a 20% decrease in intracellular K+ content within 5 min. Cell-attached patches revealed biphasic K+ channel activation with hypotonic exposure; initial activation of 165- and 40-pS K+ channels (1–3 min) was followed by a delayed but sustained reactivation of both K+ channels (> 5 min). The delayed reactivation phase was dependent on the presence of external Ca2+ and was attenuated by 10 microM gadolinium. A 28-pS nonselective cation channel (NSCC), which conducted inward Ca2+ current, was also detected during hypotonic exposure. This NSCC was stimulated by hyperpolarization and was blocked by 10 microM gadolinium. In BAEC 1) hypotonic exposure activates Ca(2+)-dependent, 165- and 40-pS K+ channels biphasically; 2) the initial phase is independent of external Ca2+, while the delayed phase requires external Ca2+; and 3) Ca(2+)-permeable, 28-pS NSCCs stimulated by membrane hyperpolarization provide a pathway for external Ca2+ influx. |
| Databáze: | OpenAIRE |
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