Altered serotonin transporter sites in Alzheimer's disease raphe and hippocampus.

This study measured serotonin transporter (5-HTT) sites in the dorsal raphe nucleus (DRN) and hippocampus in Alzheimer's disease (AD). 5-HTT sites were significantly decreased in the DRN in AD, with significant reductions occurring in the lateral wings of the DRN complex. A significant reduction in 5-HTT sites were also observed in the CA2 subfield of the hippocampus and in the entorhinal cortex in AD. The results indicate that the integrity of 5-HT neurons in the DRN may be compromised in AD, and that region specific alterations in 5-HTT sites may occur in the hippocampal complex in AD.