Cerebellar granule cells constitute the largest homogeneous neuronal population of the mammalian brain. However, they are not often used in studies that involve MPP+-neurotoxicity. Currently, it is known that the toxicity of MPP+ in cerebellar granule cells as well as in other models, including dopaminergic cells, results from activation of the apoptotic machinery after an initial oxidative burst with mitochondrial damage and energetic failure. Therefore, cerebellar granule cells serve as a good model to investigate the MPP+ effects and to study in vitro the molecular mechanism implicated in the genesis of Parkinson's disease.