@ARTICLE\{IMM2010-05871,
    author       = "D. Erritz{\o}e and K. Holst and V. G. Fr{\o}kj{\ae}r and C. L. Licht and J. Kalbitzer and F. {\AA}. Nielsen and C. Svarer and J. Madsen and G. M. Knudsen",
    title        = "A nonlinear relationship between cerebral serotonin transporter and {5-HT}(2A) receptor binding: an in vivo molecular imaging study in humans",
    year         = "2010",
    month        = "mar",
    keywords     = "Molecular neuroimaging, positron emission tomography",
    pages        = "3391-3397",
    journal      = "The Journal of Neuroscience",
    volume       = "30",
    editor       = "",
    number       = "9",
    publisher    = "",
    url          = "http://www.jneurosci.org/cgi/content/abstract/30/9/3391",
    abstract     = "Serotonergic neurotransmission is involved in the regulation of physiological functions such as mood, sleep, memory, and appetite. Within the serotonin transmitter system, both the postsynaptically located serotonin {2A} (5-HT2A) receptor and the presynaptic serotonin transporter (SERT) are sensitive to chronic changes in cerebral {5-HT} levels. Additionally, experimental studies suggest that alterations in either the {5-}HT2A receptor or {SERT} level can affect the protein level of the counterpart. The aim of this study was to explore the covariation between cerebral {5-}HT2A receptor and {SERT} in vivo in the same healthy human subjects. Fifty-six healthy human subjects with a mean age of 36 ± 19 years were investigated. The {SERT} binding was imaged with [11C]3-amino-4-(2-dimethylaminomethyl-phenylsulfanyl)-benzonitrile (DASB) and {5-}HT2A receptor binding with [18F]altanserin using positron emission tomography. Within each individual, a regional intercorrelation for the various brain regions was seen with both markers, most notably for {5-}HT2A receptor binding. An inverted {U-}shaped relationship between the {5-}HT2A receptor and the {SERT} binding was identified. The observed regional intercorrelation for both the {5-}HT2A receptor and the {SERT} cerebral binding suggests that, within the single individual, each marker has a set point adjusted through a common regulator. A quadratic relationship between the two markers is consistent with data from experimental studies of the effect on {SERT} and {5-}HT2A receptor binding of chronic changes in {5-HT} levels. That is, the observed association between the {5-}HT2A receptor and {SERT} binding could be driven by the projection output from the raphe nuclei, but other explanations are also at hand."
}