In vitro and in vivo evaluation of [125/123I]-2-[4-(2-iodophenyl)piperidino]cyclopentanol([125/123I]-OI5V) as a potential sigma-1 receptor ligand for SPECT
作者:Taiki Shigeno、Takashi Kozaka、Yoji Kitamura、Kazuma Ogawa、Junichi Taki、Seigo Kinuya、Kazuhiro Shiba
DOI:10.1007/s12149-020-01552-w
日期:2021.2
We investigated the characteristics of radio-iodinated 2-[4-(2-iodophenyl)piperidino]cyclopentanol (OI5V) as a single photon emission computed tomography (SPECT) ligand for mapping sigma-1 receptor (σ-1R), which plays an important role in stress remission in many organs. OI5V was synthesized from o-bromobenzaldehyde in three steps. OI5V was evaluated for its affinity to VAChT, σ-1 and σ-2 receptor by in vitro competitive binding assays using rat tissues and radioligands, [3H]vesamicol, ( +)-[3H]pentazocine and [3H]DTG, respectively. [125/123I]OI5V was prepared from o-trimethylstannyl-cyclopentanevesamicol (OT5V) by the iododestannylation reaction under no-carrier-added conditions. In vivo biodistribution study of [125I]OI5V in blood, brain regions and major organs of rats was performed at 2, 10, 30 and 60 min post-injection. In vivo blocking study and ex vivo autoradiography were performed to assess the binding selectivity of [125I]OI5V for σ-1 receptor. SPECT-CT imaging study was performed using [123I]OI5V. OI5V demonstrated high selective binding affinity for σ-1R in vitro. In the biodistribution study, the blood–brain barrier (BBB) permeability of [125I]OI5V was high and the accumulation of [125I]OI5V in the rat cortex at 2 min post-injection exceeded 2.00%ID/g. In the in vivo blocking study, the accumulation of [125I]OI5V in the brain was significantly blocked by co-administration of 0.5 μmol of SA4503 and 1.0 μmol of pentazocine. Ex vivo autoradiography revealed that the regional brain accumulation of [125I]OI5V was similar to σ-1R-rich regions of the rat brain. SPECT images of [123I]OI5V in the rat brain reflected the distribution of sigma receptors in the brain. This study confirmed that [125/123I]OI5V selectively binds σ-1R in the rat brain in vivo. [123I]OI5V was suggested to be useful as a σ-1R ligand for SPECT.
我们研究了放射性碘化 2-[4-(2-碘苯基)哌啶基]环戊醇(OI5V)作为单光子发射计算机断层扫描(SPECT)配体的特性,该配体可映射σ-1受体(σ-1R),σ-1R 在许多器官的应激缓解中发挥着重要作用。OI5V 是由邻溴苯甲醛通过三个步骤合成的。通过使用大鼠组织和放射性配体[3H]维沙米诺、(+)-[3H]喷他佐辛和[3H]DTG分别进行体外竞争性结合试验,评估了OI5V与VAChT、σ-1和σ-2受体的亲和力。[125/123I]OI5V是在不添加载体的条件下,通过碘锡烷化反应从邻三甲基锡环戊烷vesamicol(OT5V)制备的。在注射后 2、10、30 和 60 min 进行了[125I]OI5V 在大鼠血液、脑区和主要器官中的体内生物分布研究。为评估[125I]OI5V与σ-1受体的结合选择性,进行了体内阻断研究和体外自动放射摄影。使用[123I]OI5V进行了SPECT-CT成像研究。OI5V在体外表现出对σ-1R的高选择性结合亲和力。在生物分布研究中,[125I]OI5V的血脑屏障(BBB)通透性很高,注射后2 分钟,[125I]OI5V在大鼠大脑皮层的蓄积超过2.00%ID/g。在体内阻断研究中,同时注射 0.5 μmol 的 SA4503 和 1.0 μmol 的喷他佐辛可显著阻断[125I]OI5V 在大脑中的蓄积。体内外自动放射成像显示,[125I]OI5V在大脑中的积累区域与大鼠大脑中富含σ-1R的区域相似。大鼠大脑中[123I]OI5V的SPECT图像反映了大脑中σ受体的分布。这项研究证实,[125/123I]OI5V可选择性地结合体内大鼠大脑中的σ-1R。研究认为[123I]OI5V可作为σ-1R配体用于SPECT。