大麻素受体在大鼠视网膜中的表达和分布

Expression and distribution of cannabinoid receptors in rat retina

目的研究大麻素CB1和CB2受体在幼年、成年和老龄大鼠视网膜组织的表达和分布。方法研究采用免疫组织化学、Western印迹法和视网膜神经节细胞的上丘逆行追踪标记技术。结果 CB1和CB2受体在成年大鼠视网膜上均有较为丰富的表达,其中CB1受体的主要表达部位是外核层(ONL)、内核层(INL)和视神经节细胞层(GCL),以及外网状层(OPL)和内网状层(IPL);CB2的主要表达部位是GCL、INL、ONL的细胞膜和OPL,以及Müller胶质细胞的终足和突起上。免疫荧光双标结果显示,CB1和CB2受体在几乎所有的大鼠视网膜神经节细胞均有表达。CB1和CB2受体在幼年和老龄大鼠视网膜的表达分布与成年大鼠相似。结论大麻素CB1和CB2受体在大鼠视网膜广泛分布和表达,从幼年到老龄,其表达和分布相似,提示在出生后早期这些受体的发育已经基本完成。大麻素受体系统在视网膜信息处理的调控和视网膜神经保护中可能发挥重要作用。

Objective To investigate the expression and distribution of cannabinoid CB1 and CB2 receptors （CB1Rs and CB2Rs） in retinas of neonatal,adult and aged rats.Methods Immunohistochemistry,Western blot analysis and retrograde labeling of retinal ganglion cells were performed in the study.Results Both CB1R and CB2R positive signals were detected abundantly in the retinal cells of adult rats.CB1Rs were expressed in the outer nuclear layer （ONL）,the inner nuclear layer （INL）,the ganglion cell layer （GCL）,the outer plexiform layer （OPL） and the inner plexiform layer （IPL）.CB2Rs were widely expressed in GCL,INL,ONL and OPL as well as the end feet and the protrusion of the Müller cells.Double immunofluorescence labeling with the antibodies against cholera toxin sub unit and CB1R/CB2R showed that CB1Rs and CB2Rs were expressed in almost all of the retinal ganglion cells.The expression of CB1Rs and CB2Rs in retinas of neonatal and aged rats were similar to that of adult rats.Conclusions CB1Rs and CB2Rs are extensively expressed in retinas of rats from neonatal to aged in a similar pattern,suggesting that the development of these receptors may be terminated in the neonatal stage.Cannabinoid receptor system may play an important role in the modulation of retinal information processing and the retinal neuroprotection.