Figure 2

ATX-II induces resurgent currents in large diameter DRGs. (a) Voltage protocol and representative TTXs resurgent current traces (black traces represent recordings at −45 mV) pre and post application of ATX-II in large diameter DRGs. Lower lane shows an overlay of traces recorded pre and post ATX-II at −45 mV on a longer time scale. Arrows illustrate resurgent current and the region of mean persistent current measurements. (b) Peak resurgent current as a function of voltage recorded at 22°C (n = 8). Total current (TTXs and TTXr, black circles), peaked around −40 mV. Absolute total resurgent current (black circles) increased following application of 5 nM ATX-II (pink circles), and is mostly carried by TTXs sodium currents (square symbols). The overall resurgent current was dramatically reduced by application of TTX (grey circles). (c) TTXs resurgent current at 22°C (filled squares, n = 8) and 30°C (open squares, n = 14) is increased by application of ATX-II. Data points for 22°C are the same as in (b) and shown for better comparison. (d) Mean persistent TTXs current (black squares, determined as shown in (a) lower panel) is increased by ATX-II exposure (pink squares), whereas an increase in temperature has a smaller effect (22°C: filled squares, n = 8; 30°C: open squares, n = 14). (e) Corrected TTXs resurgent current amplitudes as a function of voltage. Corrected traces were obtained by subtraction of TTXs persistent current (shown in d) from TTXs peak resurgent current (shown in c) of each trace. At 22°C (filled symbols, n = 8) as well as at 30°C (open symbols, n = 14) corrected resurgent currents are increased by ATX-II application. * p < 0.05, paired-sample T-test.