Figure 1.

Potency of MDPV in inhibiting DA-induced Ca²⁺ signals at hDAT and dDAT. Stable cell lines expressing hDAT or dDAT were transfected with Ca_V1.2 and auxiliary subunits. Intracellular Ca²⁺ signals were determined using fluorescence microscopy under constant perfusion at 35°C in Fura2-AM loaded cells. A) Ca²⁺ signals showing the inhibitory effect of MDPV at different concentrations at hDAT, the traces are normalized to the first DA pulse, each trace is mean ± SEM of N ≥ 59 cells analyzed per MDPV concentration. B) Traces showing the inhibitory effect of MDPV at dDAT, the traces are normalized to the first DA pulse, each trace is mean ± SEM of N ≥ 77 cells analyzed per MDPV concentration. C) Dose-response curves obtained from the data shown in A and B. Since MDPV was quite weak at dDAT, the bottom of the curve fitting was constrained to zero to estimate the pIC₅₀. The fitting parameters for MDPV inhibition at hDAT and dDAT are included in Table 2.