摘要
目的分析活体正电子发射断层扫描术(PET)测试兔眼内σ_1受体的显像情况。设计实验研究。研究对象健康家兔5只和大鼠20只。方法应用放射性标记物[^(11)C]SA4503对家兔行PET的基础测定、预处理测定和置换测定及体外放射自显影术(ex vivo ARG)检查;对20只大鼠行体外放射自显影术检查,通过与σ_1受体结合测定眼球内组织的放射能摄取率。主要指标眼内σ_1受体在PET显像中的分布情况。结果PET下兔眼内虹膜睫状体与视网膜可以显像,并且通过氟呱啶醇的预处理和置换实验,证实PET图像反映了放射性标记物的特异性结合。大鼠眼内可以发现[^(11)C]SA4503大量聚集在虹膜睫状体和视网膜组织。载体负荷实验则显示[^(11)C]SA4503的受体特异性结合约占脑内总结合率的75%。σ_1受体存在于视网膜至上丘的神经轴突。体外放射自显影术证实兔眼和鼠眼内虹膜睫状体和视网膜组织存在高密度的σ_1受体。结论虹膜睫状体和视网膜中均富含σ_1受体, PET可用于活体眼内神经受体分布的研究。
Objective To investigate whether in vivo positron emission tomography （PET） can be used to show or, receptors in rabbit eyes. Design Experimental study. Participants Five rabbits and twenty Wistar rats. Methods Rabbits were performed PET study in the eye and brain in baseline, display measurement, or pretreatment conditions using [^11C]SA4503, a selective radioligand. Wistar rats were preformed ex vivo autoradiography in the eye and brain by control and blocking, or were measured uptake of [^11C]SA4503 in ocular tissues. Main Outcome Measures PET images of eye regions and specifically binding with σ1 receptors. Results PET showed radioactivity in the anterior segment including the iris-ciliary body and retina, and pretreatment or displacement by a σ1 receptor ligand （haloperidol）, suggested that the PET signal reflects radioligand-receptor binding. In rats, a high accumulation of [^11C]SA4503 was found in the iris-ciliary body and retina. A carrier-loading experiment showed that the receptor-specific binding of [^11C]SA4503 was approximately 75% of the total binding in the brain. σ1 receptors were also detected in the projecting terminals of the retina to the superior colliculus. The high density of σ1 receptors in the iris-ciliary body and retina was confirmed by ex vivo autoradiography. Conclusions The iris-ciliary body and retina are rich in σ1 receptors, and PET may be used to investigate the in vivo distribution of these neuroreceptors in the eye.
出处
《眼科》
CAS
2009年第3期198-203,共6页
Ophthalmology in China
