Inhibitory effects of talipexole and pramipexole on MPTP-Induced dopamine reduction in the striatum of C57BL/6N mice

We have investigated the effects of two novel antiparkinsonian drugs, talipexole (Domin(R)) and pramipexole, on MPTP-induced dopamine (DA) reduction in the striatum of C57BL/6N mice in comparison with those of bromocriptine. Fifteen days after MPTP treatment (25 mg/kg, i.p., given daily for 5 days), the DA content in the striatum was decreased to 40-60% of the control value. Among the three dopamine receptor agonists, talipexole and pramipexole (1 mg/kg, i.p., once a day for 20 days) more significantly suppressed the MPTP-induced DA reduction in the striatum than bromocriptine (10 mg/kg, i.p., once a day for 20 days). Talipexole did not influence [H-3]MPP+ uptake into striatal synaptosomes. These results suggest that talipexole and pramipexole have a protective effect against MPTP-induced DA reduction in the striatum of C57BL/6N mice.