TABLE 4

Effect of cocaine on D-amphetamine-induced [3H]MPP+ efflux [3H]MPP+ efflux experiments were conducted as described under Materials and Methods to determine the effect of cocaine on d-amphetamine-induced (100 nM) [3H]MPP+ efflux. The data of 3 (0.175, 0.7, 2.8, 11.2, and 50 μ M cocaine + 100 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 two-component model fit better than the one-component model only for the lowest cocaine dose (0.175 μ M) (F-test, P < 0.001). The parameter values are ± S.D.


Condition

K1

A1

K2

A2
min–1 % min–1 %
d-Amph (100 nM) 0.027 ± 0.01 22 ± 6 0.19 ± 0.02 88 ± 5
d-Amph (100 nM) + cocaine (0.175 μM) 0.031 ± 0.015 36 ± 21 0.15 ± 0.05 64 ± 19
d-Amph (100 nM) + cocaine (0.7 μM) 0.055 ± 0.002 100
d-Amph (100 nM) + cocaine (2.8 μM) 0.029 ± 0.001* 100
d-Amph (100 nM) + cocaine (11.2 μM 0.016 ± 0.001* 100
d-Amph (100 nM) + cocaine (50 μM)
0.011 ± 0.001*
100


  • * P < 0.05 compared with the value of the 0.75 μ M cocaine condition (ANOVA with a post hoc Bonferroni test)

  • This curve is statistically different from the d-Amph curve (F-test, P < 0.001)