Fig. 6
Effect of TCE on the excitability of small-sized TG neurons. (A) Typical voltage traces in response to depolarizing current injection in the absence (left) and presence (right) of 3 mM TCE. Five representative raw traces were elicited by successive depolarizing current injection (40–200 pA, 40 pA increment). Note that action potential was not triggered by the fourth stimulation (160 pA injection, arrow), whereas the membrane potential was depolarized (arrowhead) in the presence of 3 mM TCE. (B) a, TCE (3 mM)-induced changes in the absolute amplitude of rheobase currents. Each column represents the mean and SEM from eight experiments. **; p < 0.01. b, TCE (1, 3, and 10 mM)-induced changes in the amplitude of rheobase currents. Each column was normalized to the respective control (dotted line) and represents the mean and SEM from seven, eight, and eight experiments for 1, 3, and 10 mM TCE, respectively. **; p < 0.01, n.s; not significant. c, TCE (1, 3, and 10 mM)-induced changes in membrane potential. Each column represents the mean and SEM from seven, eight, and eight experiments for 1, 3, and 10 mM TCE, respectively. **; p < 0.01, n.s; not significant. (C) A typical current trace before, during, and after applying various concentrations of TCE. Small-sized TG neurons were held at a VH of − 20 mM in a voltage-clamp (V-clamp) condition. (D) A typical current trace in response to 10-mV hyperpolarizing voltage steps (300-ms duration) before, during, and after applying 10 mM TCE at a VH of − 20 mV. Inset (right) represents typical current traces (a′ and b′) with an expanded time scale. (E) Typical voltage traces in response to depolarizing current injection before (left) and during (right) the application of 3 mM TCE. Four representative raw traces were elicited by a one-fold threshold (1T; 100 pA) to the four-fold threshold (4T; 400 pA) depolarizing current injection. Note that the 1T stimulation did not trigger action potentials in the presence of 3 mM TCE (arrowhead). (F) a, Changes in the number of action potentials elicited by depolarizing current injection (1T to 4T) in the absence (black circles) and presence (red circles) of 3 mM TCE. Each point represents the mean and SEM from eight experiments. b, TCE (1, 3, and 10 mM)-induced changes in the number of action potentials elicited by 4T-depolarizing current injection. Each column was normalized to the respective control (dotted line) and represents the mean and SEM from seven, eight, and eight experiments for 1, 3, and 10 mM TCE, respectively. **; p < 0.01, n.s; not significant