Figure 8. Open-state block of Shaker K channels by the BP in K+ and Rb+ solutions. (A) Block of Shaker channels by 2 µM BP in K+ solutions. (Top inset) Currents recorded at −40 mV from a holding potential of −100 mV in the absence (black) and presence (red) of 2 µM BP. Calibration: 0.2 nA, 100 msec. (Main) Voltage dependence of Shaker channel activation (■) and fraction of channels not blocked by 2 µM BP (○). (Inset) Shaker channel currents in response to repolarization to −100 mV (from +20 mV) in the absence (black) and presence (red) of 2 µM BP, with the peak current in the BP scaled to match that of the control record. Calibration: 0.75 nA, 20 msec. (B) Block of Shaker channels by 2 µM BP in Rb+ solutions. (Top inset) Currents recorded at −40 mV from a holding potential of −100 mV in the absence (black) and presence (red) of 2 µM BP. Calibration: 0.4 nA, 100 msec. (Main) Voltage dependence of Shaker channel activation (■) and fraction of channels not blocked by 0.5 µM BP (○). Mean values from three experiments shown with standard error limits if larger than symbol. (Inset) Shaker channel currents in response to repolarization to −120 mV (from +20 mV) in the absence (black) and presence (red) of 2 µM BP, with the peak current in the BP scaled to match that of the control record. Calibration: 1.2 nA, 20 msec. Dashed line in all insets represents the zero-current level.
Image published in: Thompson J and Begenisich T (2012)
© 2012 Thompson and Begenisich. This image is reproduced with permission of the journal and the copyright holder. This is an open-access article distributed under the terms of the Creative Commons Attribution-NonCommercial-ShareAlike license
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