Reneman L, Booij J, Lavalaye J, De Bruin K, De Wolff F A, Koopmans R P, Stoof J C, Den Heeten G J
Graduate School of Neurosciences, Department of Nuclear Medicine, Academic Medical Center, Amsterdam, The Netherlands.
Synapse. 1999 Oct;34(1):77-80. doi: 10.1002/(SICI)1098-2396(199910)34:1<77::AID-SYN9>3.0.CO;2-Y.
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.
碘 - 123标记的β-CIT（2β - 甲氧羰基 - 3β - （4 - 碘苯基）托烷）和去甲β-CIT（2β - 甲氧羰基 - 3β - （4 - 碘苯基）去甲托烷）均已证明是用于成像5 - 羟色胺（5 - HT）转运体的合适放射性配体。[（123）I]去甲β - CIT在迄今报道的β - CIT类似物中对5 - HT转运体具有最高的体外亲和力。然而，迄今为止尚未有关于这两种放射性示踪剂在体内与5 - HT转运体结合的直接比较研究报道。因此，目前仍不清楚这两种放射性示踪剂中哪一种更适合用于5 - HT转运体的单光子发射计算机断层扫描（SPECT）成像。本研究的目的是在对照设计中，通过两室分析，直接比较在相同条件下大鼠体内[（123）I]β - CIT和[（123）I]去甲β - CIT与5 - HT转运体的结合情况，重点关注脑动力学特征。我们观察到，对于5 - HT转运体，[（123）I]β - CIT比[（123）I]去甲β - CIT具有更高的结合潜能和更快的动力学，这表明[（123）I]β - CIT可能比[（123）I]去甲β - CIT更适合用于SPECT成像5 - HT转运体。
