Myelin is a lipid multilayer involved in the rate of nerve transmission, and its loss is a pathological feature of multiple sclerosis in brains. Since in vivo imaging of myelin may be useful for drug development, early diagnosis, and monitoring the disease stage, we designed, synthesized, and evaluated eight novel radioiodinated 3-phenylcoumarin derivatives as imaging probes targeting myelin. In the biodistribution study using normal mice, all compounds displayed sufficient brain uptake, ranging from 2.5 to 5.0% ID/g, at 2 min postinjection. On ex vivo autoradiography, [¹²⁵I]18 and [¹²⁵I]21, which have a dimethylamino group, showed high binding affinity for myelin in the normal mouse brain. In addition, the radioactivity accumulation of [¹²⁵I]21 in the white matter of the spinal cord in the experimental autoimmune encephalomyelitis mice was lower than that in naive mice. These results suggest that [¹²³I]21 shows potential as a single photon emission computed tomography probe targeting myelin.

髓磷脂是涉及神经传递速率的脂质多层，其丢失是脑多发性硬化的病理特征。由于髓磷脂的体内成像可能对药物开发，早期诊断和监测疾病阶段有用，因此我们设计，合成和评估了八种新颖的放射性碘化的3-苯基香豆素衍生物作为靶向髓磷脂的成像探针。在使用正常小鼠进行的生物分布研究中，所有化合物在注射后2分钟均显示出足够的大脑摄取，范围为2.5至5.0％ID / g。在离体放射自显影中，[ ¹²⁵ I] 18和[ ¹²⁵ I] 21具有二甲氨基的化合物，在正常小鼠脑中对髓磷脂显示出高结合亲和力。另外，实验性自身免疫性脑脊髓炎小鼠的脊髓白质中的[ ¹²⁵ I] 21的放射性蓄积比未使用过的小鼠低。这些结果表明[ ¹²³ I] 21显示了作为靶向髓磷脂的单光子发射计算机断层扫描探头的潜力。