Radiosynthesis and in vivo evaluation of a series of substituted 11C-phenethylamines as 5-HT (2A) agonist PET tracers

Anders Ettrup, Martin Hansen, Martin A Santini, James Stephen Paine, Nicolas Gillings, Mikael Palner, S Lehel, Matthias M Herth, Jacob Madsen, Jesper Kristensen, Mikael Erik Begtrup, Gitte M Knudsen

    92 Citationer (Scopus)

    Abstract

    Purpose: Positron emission tomography (PET) imaging of serotonin 2A (5-HT2A) receptors with agonist tracers holds promise for the selective labelling of 5-HT2A receptors in their high-affinity state. We have previously validated [11C]Cimbi-5 and found that it is a 5-HT2A receptor agonist PET tracer. In an attempt to further optimize the target-to-background binding ratio, we modified the chemical structure of the phenethylamine backbone and carbon-11 labelling site of [ 11C]Cimbi-5 in different ways. Here, we present the in vivo validation of nine novel 5-HT2A receptor agonist PET tracers in the pig brain. Methods: Each radiotracer was injected intravenously into anaesthetized Danish Landrace pigs, and the pigs were subsequently scanned for 90 min in a high-resolution research tomography scanner. To evaluate 5-HT 2A receptor binding, cortical nondisplaceable binding potentials (BPND) were calculated using the simplified reference tissue model with the cerebellum as a reference region. Results: After intravenous injection, all compounds entered the brain and distributed preferentially into the cortical areas, in accordance with the known 5-HT2A receptor distribution. The largest target-to-background binding ratio was found for [11C]Cimbi-36 which also had a high brain uptake compared to its analogues. The cortical binding of [11C]Cimbi-36 was decreased by pretreatment with ketanserin, supporting 5-HT2A receptor selectivity in vivo. [11C]Cimbi-82 and [11C]Cimbi-21 showed lower cortical BPND, while [11C]Cimbi-27, [11C]Cimbi- 29, [11C]Cimbi-31 and [11C]Cimbi-88 gave rise to cortical BPND similar to that of [11C]Cimbi-5. Conclusion: [ 11C]Cimbi-36 is currently the most promising candidate for investigation of 5-HT2A receptor agonist binding in the living human brain with PET.

    OriginalsprogEngelsk
    TidsskriftEuropean Journal of Nuclear Medicine and Molecular Imaging
    Vol/bind38
    Udgave nummer4
    Sider (fra-til)681-93
    Antal sider13
    ISSN1619-7070
    DOI
    StatusUdgivet - apr. 2011

    Fingeraftryk

    Dyk ned i forskningsemnerne om 'Radiosynthesis and in vivo evaluation of a series of substituted 11C-phenethylamines as 5-HT (2A) agonist PET tracers'. Sammen danner de et unikt fingeraftryk.

    Citationsformater