TABLE 3

Effect of d-amphetamine on [3H]MPP+ efflux [3H]MPP+ efflux experiments were conducted as described under Materials and Methods. The data of three (12.5, 25, and 50 nM d-Amph) or 10 (100 nM d-Amph) independent experiments were pooled and fit to one- and two-component dissociation experiments using MLAB-PC. The parameter values are ± S.D. In all cases, the two-component model fit significantly better than the one-component model (F-test, P < 0.002).


Condition

K1

A1

K2

A2
min–1 % min–1 %
d-Amph, 12.5 nM 0.021 ± 0.005 57 ± 11* 0.18 ± 0.07 46 ± 10*
d-Amph, 25 nM 0.015 ± 0.010 26 ± 1* 0.12 ± 0.03 70 ± 13*
d-Amph, 50 nM 0.020 ± 0.010 19 ± 11* 0.15 ± 0.03 77 ± 10*
d-Amph, 100 nM
0.027 ± 0.010
22 ± 6
0.19 ± 0.02
88 ± 5
  • * The A values of the curve (constraint 4; see Materials and Methods) were significantly different (F test, P < 0.01) from the 100 nM d-Amph curve. The kinetic constants of each curve did not significantly differ from those of the 100 nM d-Amph curve

  • The entire curve (constraint 1; see Materials and Methods) was significantly different (F-test, P < 0.01) from the 100 nM d-Amph curve