Alzheimer's Disease Research Today is a free monthly online journal that collates and summarizes the latest research about Alzheimer's Disease, including details on diagnosis, memory loss, heredity, treatment, medication.

A study of the serotonin transporter in the prefrontal cortex in late-life depression and Alzheimer's disease with and without depression.

Thomas AJ, Hendriksen M, Piggott M, Ferrier IN, Perry E, Ince P, O'Brien JT

School of Neurology, Neurobiology and Psychiatry, University of Newcastle upon Tyne, Newcastle upon Tyne, UK. a.j.thomas@ncl.ac.uk

Previous studies investigating the serotonin transporter (SERT) in depression have been inconsistent and included a large proportion of subjects who had committed suicide. In Alzheimer's disease studies have generally reported a reduction in SERT density but have not compared Alzheimer's disease subjects with and without comorbid major depression. We conducted a post mortem study of SERT density in the prefrontal cortex in normal elderly, a group of elderly depressed subjects and in Alzheimer's disease subjects with and without major depression. A post mortem study comparing SERT density in the prefrontal cortex in elderly controls (n = 10), subjects with major depression (n = 8) and subjects with Alzheimer's disease with (n = 9) and without (n = 5) comorbid major depression. We used autoradiography to measure the density of [3H]CN-IMI binding (non-specific binding determined with citalopram) to the SERT in the prefrontal cortex. We found a marked reduction in specific SERT binding in the prefrontal cortex in Alzheimer's disease subjects compared with both control (P = 0.002) and depressed subjects (P = 0.004) but no difference in SERT binding between depressed and control subjects or between Alzheimer's disease subjects with and without depression. Our study confirms previous reports of a reduction in SERT binding in Alzheimer's disease but indicates this reduction is not greater in Alzheimer's disease subjects who also have had major depression. In a group of subjects more typical of late-life depression we did not identify any alterations in SERT density.

Published 27 April 2006 in Neuropathol Appl Neurobiol, 32(3): 296-303.
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