Abstract: This invention discloses that memantine (MMT) protects dopamine (DA) neurons damage through its potent anti-inflammatory effect by inhibiting microglial over-activation and the protection on DA neuron is a dose-dependent response under an effective amount of lower than 10 mg/kg. This invention also discloses that NADPH oxidase plays a critical role of neuroprotection of MMT and MMT therapy for neurodegeneration diseases and disorder acts in part through an alternative novel mechanism by reducing microglia-associated inflammation. In addition, this invention reveals that MMT is neurotrophic to DA neurons through the release of neurotrophic factors from astroglia.