Synthesis and biological evaluation of 125I/123I-labelled analogues of citalopram and escitalopram as potential radioligands for imaging of the serotonin transporter
作者:Jacob Madsen、Betina Elfving、Vibe G. Frokjaer、Birgitte R. Kornum、Gerda Thomsen、Lars Martiny、Gitte M. Knudsen
DOI:10.1002/jlcr.1841
日期:2011.4
Two novel radioligands for the serotonin transporter (SERT), [125I]3-[5-iodo-1-[4-fluorophenyl)-1,3-dihydroisobenzofuran-1-yl]-propyl}-dimethylamine ([125I]-2) and S-[125I]3-[5-iodo-1-(4-fluorophenyl)-1,3-dihydroisobenzofuran-1-yl]-propyl}-dimethylamine ([125I]-(S)-2) were synthesized in a Br/125I exchange reaction. Binding experiments in rats yielded Kd values of 0.7 ± 0.06 and 0.52 ± 0.02 nM for [125I]-2 and [125I]-(S)-2, respectively. One hour after intravenous injection of [125I]-2, 0.34% of the injected dose had accumulated in the brain. The highest hypothalamus-to-cerebellum ratio was reached 2 h after injection of [125I]-(S)-2 and amounted to 2.4. Pre-treatment experiments with paroxetine resulted in effective reduction of the target-to-cerebellum ratios. The corresponding iodine-123 labelled compound S-[123I]3-[5-Iodo-1-(4-fluorophenyl)-1,3-dihydroisobenzofuran-1-yl]-propyl}-dimethylamine [123I]-S-2 was investigated in a pig single photon emission computed tomography (SPECT) study. Between 60 and 110 min after IV injection, the midbrain-to-cerebellum ratio was 1.2. However, the uptake did not differ between high-density and medium-density regions questioning the feasibility of the radioligand in imaging cortical SERT distribution in vivo. These data suggest that the iodine-labelled derivatives of citalopram and escitalopram are not superior to another SPECT tracer for the SERT, namely [123I]ADAM. Copyright © 2010 John Wiley & Sons, Ltd.
用于血清素转运蛋白(SERT)的两种新型放射性配体,[125I]3-[5-碘-1-[4-氟苯基]-1,3-二氢异苯并呋喃-1-基]-丙基}-二甲胺([125I]- 2) 和S-[125I]3-[5-碘-1-(4-氟苯基)-1,3-二氢异苯并呋喃-1-基]-丙基}-二甲胺([125I]-(S)-2)通过 Br/125I 交换反应合成。大鼠结合实验得出 [125I]-2 和 [125I]-(S)-2 的 Kd 值分别为 0.7 ± 0.06 和 0.52 ± 0.02nM。静脉注射[125I]-2 1小时后,0.34%的注射剂量已积聚在脑中。注射[125I]-(S)-2后2小时,下丘脑与小脑的比率达到最高,达到2.4。帕罗西汀预处理实验有效降低了目标与小脑的比率。 相应的碘-123标记化合物S-[123I]3-[5-碘-1-(4-氟苯基)-1,3-二氢异苯并呋喃-1-基]-丙基}-二甲胺[123I]-S-2在猪单光子发射计算机断层扫描 (SPECT) 研究中进行了研究。静脉注射后 60 至 110 分钟之间,中脑与小脑的比率为 1.2。然而,高密度和中密度区域的摄取没有差异,这质疑放射性配体在体内皮质 SERT 分布成像中的可行性。 这些数据表明,西酞普兰和艾司西酞普兰的碘标记衍生物并不优于 SERT 的另一种 SPECT 示踪剂,即 [123I]ADAM。版权所有 © 2010 约翰威利父子有限公司