Iodine-123 labeled nor-beta-CIT as a potential tracer for serotonin transporter imaging in the human brain with single-photon emission tomography.
Iodine-123 labelled 2beta-carbomethoxy-3beta-(4-iodophenyl) (nor-beta-CIT) is an analogue of beta-CIT, which has high affinity to the serotonin transporter. Initial single-photon emission tomography (SPET) studies with [123I]nor-beta-CIT were performed in five healthy volunteers. In addition, its metabolism in plasma was investigated with gradient high performance liquid chromatography. [123I]nor-beta-CIT was prepared by a method which gave a specific radioactivity of more than 180 GBq/micromol. Unchanged [123I]nor-beta-CIT in plasma accounted for 43% and 19% of total radioactivity after 30 and 180 min, respectively. The dynamic SPET studies demonstrated a high and rapid uptake of radioactivity in the brain (6%/ID at 30 min). Highest accumulation was observed in the striatum, the mid-brain and the thalamus. The specific binding in the mid-brain was 33% higher compared with that of [123I]beta-CIT. The high radioactivity in the mid-brain is assumed to represent the accumulation of [123I]nor-beta-CIT in the serotonin transporter-rich regions, which indicates that [123I]nor-beta-CIT might be a potential tracer for visualization of serotonin transporter sites in the human brain with SPET.
Hiltunen
J
J
MAP Medical Technologies Oy, FIN-41160 Tikkakoski, Finland.
Akerman
K K
KK
Kuikka
J T
JT
Bergström
K A
KA
Halldin
C
C
Nikula
T
T
Räsänen
P
P
Tiihonen
J
J
Vauhkonen
M
M
Karhu
J
J
Kupila
J
J
Länsimies
E
E
Farde
L
L
D000328:Adult; D001921:Brain / Q000000981:diagnostic imaging*; D001923:Brain Chemistry; D002352:Carrier Proteins / Q000378:metabolism*; D002851:Chromatography, High Pressure Liquid; D003042:Cocaine / Q000031:analogs & derivatives* / Q000097:blood; D005260:Female; D006801:Humans; D007457:Iodine Radioisotopes; D008297:Male; D008562:Membrane Glycoproteins / Q000378:metabolism*; D026901:Membrane Transport Proteins; D009419:Nerve Tissue Proteins; D050486:Serotonin Plasma Membrane Transport Proteins; D015899:Tomography, Emission-Computed, Single-Photon / Q000379:methods*; D014915:Whole-Body Counting
D002352:Carrier Proteins; D007457:Iodine Radioisotopes; D008562:Membrane Glycoproteins; D026901:Membrane Transport Proteins; D009419:Nerve Tissue Proteins; C493230:SLC6A4 protein, human; D050486:Serotonin Plasma Membrane Transport Proteins; C086915:N-nor-3-(4'-iodophenyl)tropane-2-carboxylic acid methyl ester; D003042:Cocaine