[123I]-beta-CIT SPECT imaging shows reduced brain serotonin transporter availability in drug-free depressed patients with seasonal affective disorder.

Abstract

BACKGROUND:

Numerous findings indicate alterations in brain serotonin systems in seasonal affective disorder (SAD). [(123)I]-2-beta-carbomethoxy-3-beta-(4-iodophenyl)-tropane ([(123)I]-beta-CIT) labels serotonin transporters (5-HTTs) in the midbrain. We performed a [(123)I]-beta-CIT single photon emission computer tomography (SPECT) study under the hypothesis of lower [(123)I]-beta-CIT binding reflecting reduced central 5-HTT availability in depressed SAD patients.

METHODS:

Depressed SAD patients and healthy control subjects were investigated using [(123)I]-beta-CIT SPECT 4 hours and again 24 hours after tracer injection. Subjects had either never used psychotropic medication or had been drug-free for at least 6 months prior to the investigation. Specific-to-nondisplaceable partition coefficient (V(3)") was calculated for the thalamus-hypothalamus and the midbrain-pons; the cerebellum served as a reference region.

RESULTS:

Patients showed a reduction in V(3)" in thalamus-hypothalamus (2.41+/-0.3 vs. 2.84+/-0.4; p = .026) 24 hours post tracer injection (p.i.). No difference between patients and control subjects was found in midbrain-pons (1.31+/-0.2 vs. 1.42+/-0.2; p = .39). No differences were detected in the SPECT acquisitions 4 hours p.i.

CONCLUSIONS:

Depressed SAD patients showed lower specific-to-nondisplaceable [(123)I]-beta-CIT binding in the region of interest (ROI) thalamus-hypothalamus. The small size of the midbrain-pons ROI may have contributed to the failure to show a difference in this ROI as well. Similar to reduced midbrain 5-HTT availability in nonseasonal depression, depression in SAD seems to be associated with reduced 5-HTT availability to the thalamus-hypothalamus.

• Authors: M Willeit, N Praschak-Rieder, A Neumeister, W Pirker, S Asenbaum, O Vitouch, J Tauscher, E Hilger, J Stastny, T Brücke, S Kasper
• Journal: Biological psychiatry (Biol Psychiatry) Vol. 47 Issue 6 Pg. 482-9 (Mar 15 2000) ISSN: 0006-3223 [Print] United States
• PMID: 10715354 (Publication Type: Journal Article)

Chemical References

• Serotonin
• 2beta-carbomethoxy-3beta-(4-iodophenyl)tropane
• Cocaine

Topics

• Adult
• Biological Transport
• Brain (diagnostic imaging, metabolism)
• Cocaine (analogs & derivatives, pharmacokinetics)
• Depressive Disorder, Major (metabolism)
• Female
• Humans
• Male
• Middle Aged
• Seasonal Affective Disorder (metabolism)
• Serotonin (metabolism)
• Tomography, Emission-Computed, Single-Photon