Whole-cell Patch-clamp Electrophysiology

Shortly before the experiments, an aliquot of cell suspension that contained GH₃ cells or Rolf B1.T olfactory neurons, were gently harvested and transferred immediately to a home-made recording chamber which was firmly positioned on the stage of a CKX-41 inverted microscope (Olympus; YuanLi, Kaohsiung, Taiwan). Cells were immersed at room temperature (22–25 °C) in normal Tyrode’s solution, the composition of which is detailed above. Patch clamp recordings under the whole-cell mode were applied with either an RK-400 (Biol-Logic, Claix, France) or an Axopatch-200B amplifier (Molecular Devices; Bestgen Biotech, New Taipei City, Taiwan) [41 (link),59 (link)]. Patch electrodes with tip resistances of 3–5 MΩ were made of Kimax-51 glass capillaries (#34500; Kimble; Dogger, New Taipei City, Taiwan) on either a PP-83 vertical puller (Narishige; Major Instruments, New Taipei City, Taiwan) or a p-97 horizontal puller (Sutter, Novato, CA), and then fire-polished with MF-83 microforge (Narishige). Spontaneous ACs were measured by using cell-attached voltage clamp recordings, and the potential was held at the level of the resting potential (around −70 mV) [62 (link)].