Ola M Shamsul, Moore Pamela, Maddox Dennis, El-Sherbeny Amira, Huang Wei, Roon Penny, Agarwal Neeraj, Ganapathy Vadivel, Smith Sylvia B
Department of Cellular Biology and Anatomy, Medical College of Georgia, CB 2820, Augusta, GA 30912-2000, USA.
Brain Res Mol Brain Res. 2002 Nov 15;107(2):97-107. doi: 10.1016/s0169-328x(02)00444-8.
The type 1 sigma receptor (sigmaR1) is a nonopiate and nonphencyclidine binding site that has numerous pharmacological and physiological functions. In some studies, agonists for sigmaR1 have been shown to afford neuroprotection against overstimulation of the NMDA receptor. sigmaR1 expression has been demonstrated recently in retinal ganglion cells (RGC). RGCs undergo apoptosis early in diabetic retinopathy via NMDA receptor overstimulation. In the present study we asked whether RGCs cultured under hyperglycemic conditions and RGCs of diabetic mice continue to express sigmaR1. RGCs were cultured 48 h in RPMI medium containing either 45 mM glucose or 11 mM glucose plus 34 mM mannitol (osmolar control). C57BL/6 mice were made diabetic using streptozotocin. The retina was dissected from normal and streptozotocin-induced diabetic mice 3, 6 and 12 weeks post-onset of diabetes. sigmaR1 was analyzed in cells using semiquantitative RT-PCR and in tissues by semiquantitative RT-PCR, in situ hybridization, Western blot analysis and immunolocalization. The RT-PCR analysis of cultured RGCs showed that sigmaR1 mRNA is expressed under hyperglycemic conditions at levels similar to control cells. Similarly, analysis of retinas of diabetic mice showed no difference in levels of mRNA encoding sigmaR1 compared to retinas of control mice. In situ hybridization analysis showed that expression patterns of sigmaR1 mRNA in the ganglion cell layer were similar between diabetic and control mice. Western blot analysis suggested that levels of sigmaR1 in retina were similar between diabetic and control retinas. Immunohistochemical analysis of sigmaR1 showed a similar pattern of sigmaR1 protein expression between control and diabetic retina. These studies demonstrate that sigmaR1 is expressed under hyperglycemic conditions in vitro and in vivo.
1型σ受体（sigmaR1）是一种非阿片类且非苯环利定结合位点，具有众多药理和生理功能。在一些研究中，sigmaR1激动剂已被证明可提供针对N-甲基-D-天冬氨酸（NMDA）受体过度刺激的神经保护作用。最近已证实在视网膜神经节细胞（RGC）中存在sigmaR1表达。在糖尿病视网膜病变早期，RGC通过NMDA受体过度刺激而发生凋亡。在本研究中，我们探究了在高血糖条件下培养的RGC以及糖尿病小鼠的RGC是否继续表达sigmaR1。将RGC在含有45 mM葡萄糖或11 mM葡萄糖加34 mM甘露醇（渗透压对照）的RPMI培养基中培养48小时。使用链脲佐菌素使C57BL / 6小鼠患糖尿病。在糖尿病发病后3、6和12周，从正常和链脲佐菌素诱导的糖尿病小鼠中分离视网膜。使用半定量逆转录聚合酶链反应（RT-PCR）在细胞中分析sigmaR1，并通过半定量RT-PCR、原位杂交、蛋白质免疫印迹分析和免疫定位在组织中分析sigmaR1。对培养的RGC进行的RT-PCR分析表明，在高血糖条件下sigmaR1 mRNA的表达水平与对照细胞相似。同样，对糖尿病小鼠视网膜的分析表明，与对照小鼠视网膜相比，编码sigmaR1的mRNA水平没有差异。原位杂交分析表明，糖尿病小鼠和对照小鼠的神经节细胞层中sigmaR1 mRNA的表达模式相似。蛋白质免疫印迹分析表明，糖尿病视网膜和对照视网膜中sigmaR1的水平相似。对sigmaR1的免疫组织化学分析表明，对照视网膜和糖尿病视网膜中sigmaR1蛋白的表达模式相似。这些研究表明，sigmaR1在体外和体内的高血糖条件下均有表达。
