Fig. 1.

Pb²⁺ stimulates TRPC5 channels. Data from whole-cell voltage-clamp recordings (A–C) and multiwell [Ca²⁺]_i measurement (D and E) in T-rex HEK 293 cells. (A) For a cell expressing TRPC5, an example time course of current sampled at +80 mV and −80 mV during a voltage ramp and showing bath-application of 10 μM Pb²⁺ and 75 μM 2-APB (2-aminoethoxydiphenyl borate). (B) Current–voltage relationship (I–V) for the experiment in (A) showing the basal current and the current in the presence of Pb²⁺ and 2-APB. (C) Mean change in current amplitudes at −80 mV and +80 mV evoked by 10 μM Pb²⁺ in cells with (n = 5) and without (n = 3) TRPC5 over-expression. (D) Example time-series graph for [Ca²⁺]_i in response to Pb²⁺ (100, 10, 5 and 2 μM) in HEK 293 cells with TRPC5 over-expression. The data points represent the mean ± SEM for ⩾3 wells. (E) Concentration response curve for Pb²⁺ induced Ca²⁺ response. Black symbols are for tet+ TRPC5 cells (EC₅₀ 4.9 μM, slope 2.74) and white for tet− cells fitted with the Hill equation. Each point is mean ± SEM of three independent experiments.