title: The 5-HT2A receptor binding pattern in the human brain is strongly genetically determined.
abstract: With the appropriate radiolabeled tracers, positron emission tomography (PET) enables in vivo human brain imaging of markers for neurotransmission, including neurotransmitter synthesis, receptors, and transporters. Whereas structural imaging studies have provided compelling evidence that the human brain anatomy is largely genetically determined, it is currently unknown to what degree neuromodulatory markers are subjected to genetic and environmental influence. Changes in serotonin 2A (5-HT(2A)) receptors have been reported to occur in various neuropsychiatric disorders and an association between 5-HT(2A) receptor gene variants and neuropsychiatric illness susceptibility also exists. In a classical twin design involving 24 healthy male subjects (6 monozygotic twin pairs and 6 dizygotic twin pairs), we examined the relative contribution of genetic and environmental factors to interindividual variability in cortical 5-HT(2A) receptor binding as measured with [(18)F]altanserin PET imaging. The intraclass correlation coefficients were 0.67 for dizygotic and 0.87 for monozygotic twin pairs. For comparison, the intraclass correlation coefficient was 0.93 in a group of six male healthy subjects examined twice within two weeks with an identical experimental setup. Multivariate analysis was used to separate the phenotypic variance of individuals into additive genetic (heritability) effect (A), shared (family) environment (C), and non-shared (individual-specific) environment (E). Irrespective of whether a full ACE model or a reduced AE model was used to fit the data, the variance due to non-shared environment was below 10% indicating that the contribution of individual specific environmental factors to 5-HT(2A) receptor binding is limited.
authors.affiliation: Neurobiology Research Unit and Center for Integrated Molecular Brain Imaging, Copenhagen University Hospital, Rigshospitalet, N9201, 9 Blegdamsvej, DK-2100 Copenhagen, Denmark. pinborg@nru.dk
authors.forename: Lars H
authors.initials: LH
authors.lastname: Pinborg
authors.forename: Haroon
authors.initials: H
authors.lastname: Arfan
authors.forename: Steven
authors.initials: S
authors.lastname: Haugbol
authors.forename: Kirsten Ohm
authors.initials: KO
authors.lastname: Kyvik
authors.forename: Jacob V B
authors.initials: JV
authors.lastname: Hjelmborg
authors.forename: Claus
authors.initials: C
authors.lastname: Svarer
authors.forename: Vibe G
authors.initials: VG
authors.lastname: Frokjaer
authors.forename: Olaf B
authors.initials: OB
authors.lastname: Paulson
authors.forename: Soren
authors.initials: S
authors.lastname: Holm
authors.forename: Gitte M
authors.initials: GM
authors.lastname: Knudsen
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D001921:Brain / Q000000981:diagnostic imaging; D001923:Brain Chemistry / Q000235:genetics*; D006801:Humans; D007553:Isotope Labeling; D007650:Ketanserin / Q000031:analogs & derivatives; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D011877:Radionuclide Imaging; D019275:Radiopharmaceuticals; D044402:Receptor, Serotonin, 5-HT2A / Q000235:genetics* / Q000378:metabolism*; D014429:Twins, Dizygotic; D014430:Twins, Monozygotic
chemical_list: D019275:Radiopharmaceuticals; D044402:Receptor, Serotonin, 5-HT2A; C071983:altanserin; D007650:Ketanserin