TABLE 4 Effect of SRI-29574 on [^{3}H]DA accumulation

[^{3}H]DA uptake was assessed at various time points in the absence and presence of the indicated concentrations of SRI-29574. The combined data from all three experiments (Fig. 6A) (180 data points) were fit to the equation *B* = *E*_{max} × (*T*/(*T* + *t*_{1/2})), where *B* is the observed level of uptake, *T* is the time in minutes, and *t*_{1/2} is the time to half-maximal accumulation. The time course data for each drug condition were separately applied to the above equation, each of which differed only in the names of the corresponding parameters: *E*_{max1}, *E*_{max2}, *E*_{max3}, *E*_{max4}, and *E*_{max5} and *t*_{1/2-1}, *t*_{1/2-2}, *t*_{1/2-3}, *t*_{1/2-4}, and *t*_{1/2-5}. Thus, the unconstrained fit led to the reported parameter values. The data were then fit with the constraint that the *E*_{max} values were all equal. This resulted in a highly significant increase in the sum-of-squares (*F* = 18.9, *P* = 0). In contrast, fitting the data with the constraint that the *t*_{1/2} values were equal did not significantly increase the sum-of-squares (*F* = 0.46, *P* = 0.76).