Figure 4

The block of D918H and WT-DH does not require the permeation of Zn²⁺. (A–C): Effect of Zn²⁺ on currents from TRPA1 dimers measured with a stable holding potential of either +80 mV or −80 mV throughout the duration of the solution exchange. Traces were recorded sequentially but are shown on the same axes for illustrative purposes. Currents were activated by pretreatment with cinnamaldehyde (100 µM). (D) Summary of fraction change of TRPA1 WT, D918H and WT-D918H currents in response to Zn²⁺ (40 nM). I_Zn2+/I_initial was calculated from the current magnitude measured 5 seconds after application of Zn²⁺, relative to that before Zn²⁺ application. n.s. P > 0.05, ****P < 0.0001 (Sidak’s multiple comparison following two-way ANOVA); N ≥ 4. (E,F): Average data from experiments as in A-C showing the magnitude of the currents in the presence of Zn²⁺, at the concentration indicated, relative to the starting current level I_Zn2+/I_initial with a holding potential of +80 mV (E) or −80 mV (F). Note that while the potentiation of WT channels by Zn²⁺ is very sensitive to membrane potential, the inhibition of the D918H and WT-D918H channels is not very sensitive to membrane potential.