@ARTICLE\{IMM2010-05872,
    author       = "J. Kalbitzer and D. Erritz{\o}e and K. K. Holst and F. {\AA}. Nielsen and L. Marner and S. Lehel and T. Arentzen and T. L. Jernigan and G. M. Knudsen",
    title        = "Seasonal Changes in Brain Serotonin Transporter Binding in Short Serotonin Transporter Linked Polymorphic Region-Allele Carriers but Not in Long-Allele Homozygotes",
    year         = "2010",
    keywords     = "Molecular neuroimaging, positron emission tomography",
    pages        = "1033-1039",
    journal      = "Biological Psychiatry",
    volume       = "67",
    editor       = "",
    number       = "11",
    publisher    = "",
    url          = "http://dx.doi.org/10.1016/j.biopsych.2009.11.027",
    abstract     = "Background

A polymorphism in the promoter region of the serotonin transporter gene (5-HTTLPR) has been associated with seasonality both in patients with seasonal affective disorder and in the general population.

Method

We used in vivo molecular imaging to measure cerebral serotonin transporter (5-HTT) binding in 57 healthy Scandinavians and related the outcome to season of the year and to the {5-HTTLPR} carrier status.

Results

We found that the number of daylight minutes at the time of scanning correlated negatively with {5-HTT} binding in the putamen and the caudate, with a similar tendency in the thalamus, whereas this association was not observed for the midbrain. Furthermore, in the putamen, an anatomic region with relatively dense serotonin innervation, we found a significant gene × daylight effect, such that there was a negative correlation between {5-HTT} binding and daylight minutes in carriers of the short {5-HTTLPR} allele but not in homozygote carriers of the long allele.

Conclusions

Our findings are in line with {S-}carriers having an increased response in neural circuits involved in emotional processing to stressful environmental stimuli but here demonstrated as a endophenotype with dynamic changes in serotonin reuptake."
}