Comparative in vivo study of iodine-123-labeled beta-CIT and nor-beta-CIT binding to serotonin transporters in rat brain.
Both iodine-123-labeled beta-CIT (2beta-carbomethoxy-3beta-(4-iodophenyl)tropane) and nor-beta-CIT (2beta-carbomethoxy-3beta-(4-iodophenyl)nortropane) have shown to be suitable radioligands for imaging serotonin (5-HT) transporters. [(123)I]nor-beta-CIT has the highest in vitro affinity for 5-HT transporters among beta-CIT analogs reported so far. However, no direct comparison-studies of these two radiotracers as to their in vivo binding to 5-HT transporters have been reported so far. Therefore, it is still unclear which of the two radiotracers is more suitable for single photon emission computed tomography (SPECT) imaging of 5-HT transporters. The purpose of this study was to compare directly in a controlled design the in vivo [(123)I]beta-CIT and [(123)I]nor-beta-CIT binding to 5-HT transporters under the same conditions in rats with the focus on brain kinetic characteristics by means of a two-compartment analysis. We observed that [(123)I]beta-CIT has a higher binding potential and faster kinetics for 5-HT transporters than [(123)I]nor-beta-CIT, suggesting that [(123)I]beta-CIT may be a more suitable radioligand than [(123)I]nor-beta-CIT for imaging 5-HT transporters with SPECT.
Reneman
L
L
Graduate School of Neurosciences, Department of Nuclear Medicine, Academic Medical Center, Amsterdam, The Netherlands. l.reneman@amc.uva.nl
Booij
J
J
Lavalaye
J
J
De Bruin
K
K
De Wolff
F A
FA
Koopmans
R P
RP
Stoof
J C
JC
Den Heeten
G J
GJ
D000818:Animals; D001921:Brain / Q000000981:diagnostic imaging; D001923:Brain Chemistry / Q000187:drug effects*; D002352:Carrier Proteins / Q000378:metabolism*; D003042:Cocaine / Q000031:analogs & derivatives* / Q000378:metabolism; D007457:Iodine Radioisotopes; D007700:Kinetics; D008297:Male; D008562:Membrane Glycoproteins / Q000378:metabolism*; D026901:Membrane Transport Proteins; D008959:Models, Neurological; D009419:Nerve Tissue Proteins; D011485:Protein Binding; D051381:Rats; D017208:Rats, Wistar; D012701:Serotonin / Q000378:metabolism*; D050486:Serotonin Plasma Membrane Transport Proteins; D015899:Tomography, Emission-Computed, Single-Photon
D002352:Carrier Proteins; D007457:Iodine Radioisotopes; D008562:Membrane Glycoproteins; D026901:Membrane Transport Proteins; D009419:Nerve Tissue Proteins; D050486:Serotonin Plasma Membrane Transport Proteins; C493232:Slc6a4 protein, rat; C086915:N-nor-3-(4'-iodophenyl)tropane-2-carboxylic acid methyl ester; D012701:Serotonin; C069723:2beta-carbomethoxy-3beta-(4-iodophenyl)tropane; D003042:Cocaine