XB-IMG-175671
Xenbase Image ID: 175671
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Figure 1. A reliable approach to recording APs in Xenopus oocytes. (A and B) Schematic of the loose-clamp electronics used to measure APs with a TEVC amplifier. The dashed red box shows the adapted circuitry, which is enlarged in B. Electrical recordings in oocytes injected 2–4 d prior with an RNA mixture for sodium and potassium channels: 10 ng Nav1.4, 2.5 ng Navβ1, 5 ng Kv7.2, 5 ng Kv7.3, and 0.6 ng ShakerΔ. (C) In the loose clamp, 1-ms voltage pulses were applied to depolarize the membrane. Top: Membrane current produced by the depolarizing stimulus. Bottom: Membrane depolarization. The inset in C shows a subthreshold depolarization (black trace), and the next pulse stimulated a voltage change that is an all-or-none AP (red trace). (D) For the same RNA mixture as in C, the APs in oocytes were examined with paired pulses to measure the refractory period. The 1-ms pulses (top) were 16 ms apart for the traces on the left. The black traces for the pulses were for stimuli of the same amplitude, whereas red traces signify that the second pulse was of greater amplitude than the first. The corresponding membrane voltage recordings are shown in the bottom left with the same color coding. On the right side, the 1-ms depolarizing pulses (top) were 9 ms apart. The black traces were for stimuli of the same amplitude, whereas blue traces signify that the second pulse was of greater amplitude. The corresponding membrane voltage recordings are shown in the bottom right. The second stimulus was increased four times without eliciting an AP. Image published in: Corbin-Leftwich A et al. (2018) © 2018 Corbin-Leftwich et al. Creative Commons Attribution-NonCommercial-ShareAlike license Larger Image Printer Friendly View |