Project Summary

Peter S. Talbot, M.B., Ch.B. (Young Investigator 2004) of New York State Psychiatric Institute/Columbia University, using PET imaging of living brains, aims to develop a new way to measure the neurotransmitter serotonin (5-HT), levels of which may be reduced in patients with depression. PET allows for imaging of a neurotransmitter in a living brain by measuring how changing levels of the neurotransmitter affects the binding to a suitable PET radiotracer. But not all radiotracers are sensitive to alterations in neurotransmitter levels, and the technique has not been successful in the 5-HT system. Dr. Talbot aims to reliably and safely decrease 5-HT in 8 healthy human subjects by a dietary technique called rapid tryptophan depletion (RTD). He hypothesizes a decrease in 5-HT will be reflected by increased binding of the newly available PET serotonin transporter radiotracer [11C]DASB. Initial results in the first three healthy male subjects support the hypothesis. If these results are confirmed in a larger group, the technique of RTD coupled with [11C]DASB imaging might provide a method to evaluate 5-HT synaptic levels in the living brain. Studies will then be performed in eight people with major depressive disorder, potentially providing a more direct insight into the role of abnormal serotonergic function in depression than previously available.

Program Area: MOOD DISORDERS\Unipolar Depression

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