In the current study, we used the mitochondria complex I inhibitor 1-methyl-4-phenylpyridinium (MPP+) and investigated whether HO-1 behaves distinctively between neurons and astrocytes under the condition of neurotoxicity related to PD in primary cultured ventral mesencephalon (VM) neurons and astrocytes. This evidence concerns the gene HMOX1 and Parkinson disease.