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. 2013 Nov 5;105(9):2055–2063. doi: 10.1016/j.bpj.2013.08.031

Figure 1.

Figure 1

Basic characterization of GR-WT in Xenopus laevis oocytes. (A) Typical photocurrent traces of GR-WT at different extracellular pH conditions and holding voltages ranging from −125 mV up to +75 mV in 25-mV steps. A 200-ms pulse of green light (550 ± 25 nm) was used for activation of GR. (B) I(E)-plot of stationary currents with extrapolated reversal voltages (mean ± SE, n ≥ 13). Currents were normalized to stationary photocurrent at pHo 7.5 and 0 mV (Iref). (Arrows) Conditions for action spectra measurements. For pHo 6.0, 7.5, and 9.0 the reversal voltage was determined by nonlinear regression (broken line) according to I(E) = I0 + AebE. (C) Plot of the determined reversal voltages Erev versus pHo, fitted by linear regression. The reversal voltages calculated by the Nernst equation (ENernst) are based on an intracellular pHi of 7.4 (mean ± SD, n ≥ 13). (D) Action spectra of stationary outward directed photocurrents at pHo 7.5 (green) and 3.8 (red) at 0 mV as well as for inward directed photocurrents at pHo 3.8 and −120 mV (magenta). Currents were normalized to the maximal stationary currents. (Inset) Action spectra maxima (mean ± SD, n ≥ 13).