TABLE 3

Shift experiments of substrates for DAT-mediated [3H]MPP+ release

Eight point dose-response curves were generated for DAT-mediated [3H]MPP+ release in the absence and presence of the indicated blockers (cocaine and GBR12909). The data (n = 3) were fit to the dose-response equation as described under Materials and Methods for the best-fit estimates of the EC50 (nM ± S.D.) and EMAX (% ± S.D.) values. Apparent Ke values (nM) were calculated as described under Materials and Methods.

DrugNo BlockerCocaine, 1.0 μMGBR12909, 0.5 nM
d-Amphetamine
    EC506.4 ± 1.040 ± 621 ± 3
    EMAX102 ± 5107 ± 4107 ± 4
    Ke190 ± 280.22 ± 0.03
PAL-192
    EC50644 ± 1285546 ± 15275818 ± 833
    EMAX77 ± 356 ± 5*70 ± 3*
    Ke131 ± 360.062 ± 0.009
PAL-193
    EC50202 ± 753917 ± 7342878 ± 385
    EMAX70 ± 553 ± 3*62 ± 2*
    Ke54 ± 100.038 ± 0.005
PAL-287
    EC5014 ± 394 ± 1931 ± 4
    EMAX97 ± 5108 ± 7102 ± 3
    Ke175 ± 350.41 ± 0.05
PAL-1045
    EC50106 ± 19422 ± 99148 ± 14
    EMAX84 ± 379 ± 481 ± 1
    Ke335 ± 781.26 ± 0.12
PAL-1046
    EC5015 ± 464 ± 1229 ± 2
    EMAX100 ± 5101 ± 4100 ± 1
    Ke306 ± 570.54 ± 0.04
  • * P < 0.05 compared with the EMAX value of the “no blocker” condition (Student's t test).