The novel type B MAO inhibitor PF9601N enhances the duration of L-DOPA-induced contralateral turning in 6-hydroxydopamine lesioned rats

The present study examined the effect of the highly potent and selective MAO B inhibitor PF9601N on L-DOPA-induced rotational behavior in unilateral nigrostriatal 6-hydroxydopamine lesioned rats. Three doses of PF9601N (20, 40 and 60 mg/kg) were administered 30 min before an injection of L-DOPA (25 mg/kg), and both contralateral and ipsilateral rotational behavior was measured. In addition, we also studied the effect produced by another MAO B inhibitor, deprenyl (20 mg/kg), the MAO A inhibitor, clorgyline (20 mg/kg), and the dopamine reuptake inhibitor, GBR2909 (7.5 mg/kg) on L-DOPA-induced rotational behavior. The results showed that PF9601N plus L-DOPA significantly enhanced the duration of contralateral rotational behavior with respect to L-DOPA plus vehicle in a dose-related manner. At the dose of 40 and 60 mg/kg, PF9601N produced significantly more overall contralateral turning than L-DOPA plus vehicle, and at the dose of 60 mg/kg, PF9601N produced significantly more turning behavior than L-DOPA plus deprenyl. These results suggest that PF9601N may be used as a novel tool in the treatment of Parkinson's disease.