Striatal monoaminergic terminals in Lewy body and Alzheimer's dementias

Vesicular monoamine transporter type 2 and benzodiazepine binding site expressions were examined with quantitative autoradiography in postmortem striata from 19 patients with dementia with Lewy bodies, seven patients with dementia with Lewy bodies and Alzheimer's disease, 12 patients with Alzheimer's disease, and eight neurologically normal subjects. Striatal vesicular monoamine transporter type 2 expression in dementia with Lewy bodies and in dementia with Lewy bodies plus Alzheimer's disease was reduced significantly, indicating degeneration of nigirostriatal projections. Striatal benzodiazepine binding site expression was unchanged, indicating preserved intrinsic striatal neuropil. Vesicular monoamine transporter type 2 and benzodiazepine binding site expressions were each preserved in Alzheimer's disease striatum. We conclude that dementia with Lewy bodies may be distinguished from Alzheimer's disease by postmortem examination or by future in vivo measurements of the striatal vesicular monoamine transporter type 2.