Positron-Emitting N-(18F)Fluoroalkyl and (18F)Fluoropyrrolidinyl Analogues of Eticlopride as Potential in Vivo Radioligands for Dopamine D2 Receptors.
作者:Minoru MAEDA、Shigeki SASAKI、Toshimitsu FUKUMURA、Etsuko FUKUZAWA、Kiyoko WATANABE、Masaharu KOJIMA、Takashi TAHARA、Kouji MASUDA、Yuichi ICHIYA
DOI:10.1248/cpb.40.1793
日期:——
N-Fluoroalkyl and 4-fluoropyrrolidinyl eticlopride analogues with high affinity toward central nervous system dopamine D2 receptors in vitro were labelled with positron emitting fluorine-18 (t1/2=110 min), and their in vivo biodistribution was investigated in rats. N-[18F]Fluoro-ethyl and -propyl eticlopride derivatives showed poor in vivo selectivity in the rat brain. On the other hand, 4-[18F]fluoropyrrolidinyl eticlopride exhibited almost constant and relatively high striatal concentration. The striata/cerebellar radioactivity ratio, which corresponds to the ratio of a brain D2 receptor-rich to poor region, gradually increased to 5.2-6.4, 90 min after the injection. The striatal accumulation was selectively inhibited by pre-injection of haloperidol, a dopamine D2 antagonist, without affecting accumulation in other tissues. Thus, the selective striatal accumulation of 4-[18F]fluoropyrrolidinyl eticlopride in striatal tissue appears to be due to the specific binding to dopamine D2 receoptors.
体外对中枢神经系统多巴胺 D2 受体具有高亲和力的 N-氟烷基和 4-氟吡咯烷基艾氯必利类似物用正电子发射氟 18 (t1/2=110 min) 标记,并在大鼠体内研究了它们的生物分布。 N-[18F]氟乙基和氟丙基艾氯必利衍生物在大鼠脑中表现出较差的体内选择性。另一方面,4-[18F]氟吡咯烷基艾氯必利表现出几乎恒定且相对较高的纹状体浓度。注射90分钟后,纹状体/小脑放射性比值(对应于大脑D2受体丰富区与贫乏区的比率)逐渐增加至5.2-6.4。预先注射多巴胺 D2 拮抗剂氟哌啶醇可选择性抑制纹状体的积累,而不影响其他组织的积累。因此,纹状体组织中4-[18F]氟吡咯烷基艾氯必利的选择性纹状体积累似乎是由于与多巴胺D2受体的特异性结合。