BACKGROUND Prior studies suggest that serotoninergic neurotransmission reduces β-
amyloid (Aβ) production. OBJECTIVE To determine whether serotoninergic system degeneration in
Parkinson disease promotes Aβ deposition, using in vivo positron emission tomographic probes of
serotonin system integrity and Aβ deposition. DESIGN, SETTING, AND PATIENTS Cross-sectional study of 13 subjects with
Parkinson disease from the
movement disorders clinics at the University of Michigan Health System and Veterans Affairs Ann Arbor Healthcare System, with positron emission tomography using the
serotonin transporter ligand carbon 11 ([11C])-labeled 3-amino-4-(2-dimethylaminomethyl-phenylsulfaryl)-benzonitrile (DASB) and the Aβ
ligand [11C]
Pittsburgh compound B. RESULTS Inverse correlations were found between DASB and
Pittsburgh compound B distribution volume ratios in the neocortex (ρ = -0.577; P = .04) and striatum (ρ = -0.780; P = .002). CONCLUSION Serotoninergic system degeneration in
Parkinson disease may promote the development of cerebral amyloidopathy.