AbstractThe family of dopamine D2‐like receptors represents an interesting target for a variety of neurological diseases, e. g. Parkinson's disease (PD), addiction, or schizophrenia. In this study we describe the synthesis of a new set of fluorescent ligands as tools for visualization of dopamine D2‐like receptors. Pharmacological characterization in radioligand binding studies identified UR‐MN212 (20) as a high‐affinity ligand for D2‐like receptors (pKi (D2longR)=8.24, pKi (D3R)=8.58, pKi (D4R)=7.78) with decent selectivity towards D1‐like receptors. Compound 20 is a neutral antagonist in a Go1 activation assay at the D2longR, D3R, and D4R, which is an important feature for studies using whole cells. The neutral antagonist 20, equipped with a 5‐TAMRA dye, displayed rapid association to the D2longR in binding studies using confocal microscopy demonstrating its suitability for fluorescence microscopy. Furthermore, in molecular brightness studies, the ligand's binding affinity could be determined in a single‐digit nanomolar range that was in good agreement with radioligand binding data. Therefore, the fluorescent compound can be used for quantitative characterization of native D2‐like receptors in a broad variety of experimental setups.
摘要多巴胺 D2 样受体家族是治疗各种神经系统疾病(如帕金森病(PD)、成瘾或精神分裂症)的有趣靶点。帕金森病(PD)、成瘾症或精神分裂症。在这项研究中,我们描述了一组新的荧光配体的合成过程,它们是多巴胺 D2 样受体可视化的工具。在放射性配体结合研究中进行的药理学表征发现,UR-MN212(20)是 D2 样受体的高亲和性配体(pKi (D2longR)=8.24, pKi (D3R)=8.58, pKi (D4R)=7.78 ),对 D1 样受体具有良好的选择性。在 D2longR、D3R 和 D4R 的 Go1 激活试验中,化合物 20 是一种中性拮抗剂,这对于使用全细胞进行的研究来说是一个重要特征。中性拮抗剂 20 配有 5-TAMRA 染料,在使用共聚焦显微镜进行的结合研究中显示出与 D2longR 的快速结合,这表明它适用于荧光显微镜。此外,在分子亮度研究中,配体的结合亲和力可在个位数纳摩尔范围内确定,与放射性配体的结合数据十分吻合。因此,该荧光化合物可用于在各种实验装置中对原生 D2 样受体进行定量表征。