CHAT and Parkinson disease: As with PD and PDD, previous research in Mn neurotoxicity has focused on the involvement of dopaminergic systems despite evidence that Mn has demonstrable effects on the neuronal cholinergic synapse including choline uptake, choline acetyltransferase (ChAT) activity, acetylcholine release, and the regulation of acetylcholinesterase (AChE) (Finkelstein et al., 2007).