±8-OH-DPAT improves the efficacy of L-DOPA on the FAS test. In a counterbalanced within-subjects design (n = 8), baseline motor disability was established by a pretreatment of vehicle followed 5 min later by another vehicle injection (VEH+VEH). The antiparkinsonian efficacy of L-DOPA was determined by injection of vehicle followed by L-DOPA + benserazide (12 + 15 mg/kg, i.p.; VEH+LD). Finally, the effects of 5-HT1AR stimulation on L-DOPA efficacy were examined by injection of ±8-OH-DPAT (0.1 or 1.0 mg/kg, i.p.) followed by L-DOPA + benserazide, abbreviated D(0.1) + LD or D(1.0) + LD, respectively. Bars show the effects of treatments on FAS performance expressed as mean percentages of nonlesioned (Intact) FAS ± SEM in that same treatment condition. Effects were analyzed by a one-way ANOVA and significant differences were established by appropriate post hoc comparisons. *P < 0.05 vs. VEH+VEH; +P < 0.05 vs. VEH+LD.