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Potassium channel "inactivation" induced by soft-glass patch pipettes
1Department of Physiology, School of Medicine, University of Pennsylvania, Philadelphia 19104-6085.
Biophysical Journal
|January 1, 1988
Summary
Researchers investigated potassium currents in rat pituitary cells. Soft glass pipettes caused fast current inactivation, likely due to glass ion contamination, unlike hard glass pipettes.
Area of Science:
- Neuroscience
- Cell Physiology
Background:
- Pituitary pars intermedia cells play a role in hormone regulation.
- Understanding ion channel function is crucial for cellular electrophysiology.
Purpose of the Study:
- To characterize potassium currents in rat pituitary pars intermedia cells.
- To investigate the influence of recording pipette material on potassium current properties.
Main Methods:
- Primary cell culture of rat pituitary pars intermedia cells.
- Whole-cell patch-clamp electrophysiology using hard-glass and soft-glass pipettes.
- Recording of voltage-dependent potassium currents.
Main Results:
- Potassium currents in these cells are primarily voltage-dependent.
- Slow inactivation of potassium currents was observed with hard-glass pipettes and EGTA.
- Fast inactivation was observed with soft-glass pipettes, suggesting ion-induced channel block.
Conclusions:
- The material of patch pipettes can significantly affect the measurement of ion channel kinetics.
- Di- or multivalent cations leaching from soft glass likely cause potassium channel block.
- Careful selection of recording tools is essential for accurate electrophysiological studies.