Axopatch 200b amplifier

Whole-cell experiments were carried out using tsA201 cells for the greatest expression, while cell-attached experiments utilized mouse ltk- fibroblasts for their lower levels of endogenous K⁺ currents. As previously described¹² cells were plated on coverslips and transfected the next day with Lipofectamine as per the manufacturer’s protocol with 2 µg of GFP-tagged WT or mutant KCNQ1 in pcDNA3. Recordings were made 24–48 h after transfection.
Whole-cell currents were recorded using an Axopatch 200B amplifier, Digidata 1440A, and pClamp 10 software (Clampex10.1, Molecular Devices, San Jose, CA, USA). Electrode resistances were between 1–2 MΩ, with series resistances <4 MΩ. and compensation of ~80% was applied with a calculated voltage error of ~1 mV/nA current. Currents were sampled at 10 kHz and filtered at 2–5 kHz¹² . Single-channel recordings were acquired with an Axopatch 200B amplifier, Digidata 1330 A and pClamp 9 software (Molecular Devices, San Jose, CA, USA). After fire polishing, single-channel electrode resistances were between 40 and 60 MΩ. Prior to use, electrodes were coated with Sylgard (Dow Corning, Midland, MI, USA). Records were sampled at 10 kHz, low-pass filtered at 2 kHz at acquisition using a −3 dB, four-pole Bessel filter, and digitally filtered at 200 Hz for presentation and analysis using Clampfit 10.1^{12 ,90 (link),91 (link)}.