Positive immunoreactivity for vesicular monoamine transporter 2 in Lewy bodies and Lewy neurites in substantia nigra.

Vesicular monoamine transporter 2 (VMAT2) is responsible for packing dopamine into vesicles, and reduces the effects of neurotoxins by sequestering them into vesicles. In this report, we tested the hypothesis that VMAT2 is associated with Lewy body (LB) formation by immunohistochemical staining of midbrain and cortical sections of autopsied brains of patients with Parkinson's disease (PD) and diffuse Lewy body disease (DLBD) for VMAT2 using a polyclonal antibody against VMAT2. LBs in the substantia nigra (SN) of PD and DLBD were immunoreactive for VMAT2, especially in the peripheral zone. Previous electron microscopic studies also revealed the presence of numerous dense core vesicles around the LBs, suggesting that these vesicles are related to LB formation. Indeed, the presence of a few vesicle-linked proteins such as synaptophysin and chromogranin A in LBs has been reported. Together with the low expression of VMAT2 in the SN of PD, the involvement of VMAT2 in LBs of the SN suggests the association of this protein in the neurodegeneration of nigral neurons in PD.