Manganese accumulation in striatum of mice exposed to toxic doses is dependent upon a functional dopamine transporter

The objective of this study was to determine the importance of the dopamine transporter (DAT) in manganese transport. Excessive manganese exposure is associated with a neurotoxicological disease known as manganism characterized by a specific accumulation of manganese in dopamine-rich brain regions. It has been hypothesized that the DAT mediates this specific transport, but its role in manganese neurotoxicity has not been directly examined. We examined brain tissues from manganese-exposed dopamine transporter knockout (DAT-KO) and wild-type (WT) mice. There was significantly less (p<0.05) manganese in the striatum of exposed DAT-KO mice compared to WT. However, the absence of a functioning DAT did not affect manganese accumulation in other brain regions examined. Furthermore, both iron and divalent metal transporter levels (two known modulators of brain manganese) were similar between DAT-KO and WT mice in all brain regions. These studies demonstrate that the DAT is involved in the facilitation of striatal manganese accumulation and that it may play a critical role in mediating manganese neurotoxicity.