Unilaterally lesioned rats were injected (i.p.) with varying doses of PG01037 (0 to 25 mg/kg) followed immediately with a constant dose of L-dopa and benserazide (8 mg/kg each). The percent of the mean total AIMs score ± S.E.M. (n ≥ 8) relative to vehicle controls as a function of the dose of PG01037 is shown. The mean values ± S.E.M. for the normalized total AIMs values as a function of PG01037 concentrations are as follows: a) 1 mg/kg, 88.6 ± 9.1, b) 2.5 mg/kg, 86.6 ± 5.9, c) 5 mg/kg, 55.2 ± 7.6, d) 10 mg/kg, 42.4 ± 7.1 and e) 25 mg/kg, 17.3 ± 8.9. A graph of the percent change in the AIMs score minus the locomotor component as a function of the dose of PG01037 is essentially identical to the one shown in this figure. At doses of 1 and 2.5 mg/kg there is not a significant attenuation of the total AIMs score. However, at doses of 5, 10 and 25 mg/kg there was a significant reduction (p < 0.0001) of total AIM scores relative to the vehicle controls. The calculated IC50 value was found to be 7.4 mg/kg using a reversible one site fit model constraining the maximum and minimum mean values to 100% (no test drug) and 0%, respectively.