Stimulation, protection and regeneration of dopaminergic neurons by 9-methyl-β-carboline: a new anti-Parkinson drug?

β-carbolines are potential endogenous and exogenous neurotoxins that may contribute to the pathogenesis of Parkinson’s disease (PD). 9-methyl-β-carboline exhibits multimodal effects that could be beneficial in the treatment of PD. It shows stimulatory effects to dopaminergic neurons by increasing the expression of tyrosine hydroxylase and its transcription factors in pre-existing dopa decarboxylase immunoreactive neurons. Furthermore, 9-methyl-β-carboline has emerged as a substance with the rare property of a protective and regenerative/restorative potential for dopaminergic neurons by inducing gene expression of several neurotrophic factors and decreasing apoptotic cell signals. It reduces protein levels of α-synuclein and inhibits monoamine oxidase A and B. Finally, 9-methyl-β-carboline acts on multiple targets in the inflammatory cascade by inhibiting the proliferation of microglia, by decreasing chemotactic cytokines and by creating an anti-inflammatory environment in the CNS. This article summarizes ...