Fig. 6.

Muscarinic antagonist, dicyclomine, enhances l-DOPA's antiparkinsonian effect and attenuates dyskinesia in Pitx3^ak/ak mice. Dicyclomine (15 mg/kg, i.p.) was given 30 min before the final injection of l-DOPA (25 mg/kg) in Pitx3^ak/ak mice treated repeatedly with l-DOPA (25 mg/kg, twice a day, i.p.) for 5 wk. (A) Three-paw dyskinesia was markedly decreased by dicyclomine. (B) Dicyclomine significantly enhanced rearing activity compared with vehicle/l-DOPA. (n = 12–16 per group; *P < 0.05, two-way ANOVA followed by Tukey post hoc test). (C and D) The muscarinic receptor antagonist dicyclomine (Dicy) had no impact on general locomotor activity of Pitx3^ak/+ heterozygous mice in the open-field test for either individual time blocks (5 min, C) or the total time (30 min, D) tested compared with vehicle (n = 12 per group). The data for A to D represent the mean ± SEM.