Fig. 5.
Effect of test agents on DAT-mediated release of [3H]MPP+ (A) or [3H]DA (B). (A) SRI-29574 had no significant effect on the d-amphetamine EC50 or Emax value. SRI-29213, in contrast, significantly increased the EC50 value and also decreased the Emax value. GBR12935, a competitive DAT uptake inhibitor, shifted the d-amphetamine release curve to the right in a parallel fashion without changing the Emax value. (B) Similar results were observed for [3H]DA release. Each data point is the mean ± S.D. of three separate experiments. The data were fit to a one-component dose-response curve equation for the best-fit estimates of the EC50 (± S.D.) and Emax (± S.D.), which are reported in Table 2.