Figure 2. Voltage-independent effects by extracellular Cu²⁺ on inward and outward TRPM2 channel currents.

(A) ADPR-induced currents mediated by the hTRPM2 channels at a holding membrane potentials (HP) of +40 mV (outward currents) or −40 mV (inward currents) and the effect of 100 µM Cu²⁺. The dotted lines indicate the baseline. (B–C) Summary of the outward or inward current amplitude before and after exposure to Cu²⁺ and upon washout, as shown in (A). The number of cells examined in each case is 4. ***, p<0.005 compared with the currents before and after exposure to the indicated Cu²⁺. (D) Summary of the time for 90% inhibition at both 40 mV and −40 mV, there is no significant difference between these groups.