Dopaminergic nigrostriatal projections regulate neural precursor proliferation in the adult mouse subventricular zone.

An understanding of the regulators of neurogenesis in the normal and diseased brain is necessary in order to recruit endogenously produced neural precursors for cell replacement in neurodegenerative disorders such as Parkinson's disease. The location of dopaminergic projections from the midbrain to the neostriatum and nucleus accumbens overlaps with the most active region of neurogenesis in the adult brain, the subventricular zone of the anterior lateral ventricle. This suggests that dopamine may contribute to regulation of the subventricular niche of adult neurogenesis. Here, we show in adult mice that destruction of the dopaminergic neurons in the substantia nigra and ventral tegmental area in a 6-hydroxydopamine model of Parkinson's disease reduced the number of proliferating neural precursors in the subventricular zone of the anterior lateral ventricle by approximately 40%. The effect on neural precursor proliferation correlated with the extent of dopaminergic denervation in the neighboring neostriatum. This identifies dopamine as one of the few known endogenous regulators of adult neurogenesis with implications for the potential use of endogenous neural precursors in cell replacement strategies for Parkinson's disease.