Patch Clamp Recordings of Adherent Cells

Shortly before the experiments, cells were carefully detached from culture dishes, and an aliquot of cell suspension was transferred to a homemade chamber and allowed to settle to the bottom. The chamber was firmly positioned on the stage of a CKX-41 inverted microscope (Olympus; Yuan-Li, Kaohsiung, Taiwan), and cells were immersed at room temperature (20–25 °C) in normal Tyrode solution, the ionic compositions of which are described above. Patch clamp recordings in the whole-cell configuration were performed with the help of either an RK-400 (Bio-Logic, Claix, France) or an Axopatch-200B patch amplifier (Molecular Devices; Bestogen Biotech, New Taipei City, Taiwan) [10 (link),22 (link),74 (link)]. Patch electrodes with tip resistances of 3–5 MΩ were made of Kimax^®-51 glass capillaries (#34500-99; Kimble^®; Dogger, New Taipei City, Taiwan) by using a PP-830 vertical puller (Narishige; Major Instruments, New Taipei City, Taiwan), and then fire-polished with an MF-83 microforge (Narishige). The junction potential, which occurred due to different compositions between extracellular and intracellular solutions, was zeroed shortly before GΩ-seal formation, and the whole-cell data were then corrected.