Bouskila Joseph, Javadi Pasha, Elkrief Laurent, Casanova Christian, Bouchard Jean-François, Ptito Maurice
School of Optometry, University of Montreal, Montreal, QC, Canada H3T 1P1; Biomedical Sciences, Faculty of Medicine, University of Montreal, Montreal, QC, Canada H3T 1J4.
School of Optometry, University of Montreal, Montreal, QC, Canada H3T 1P1.
Neural Plast. 2016;2016:3127658. doi: 10.1155/2016/3127658. Epub 2016 Feb 8.
The endocannabinoid (eCB) system is widely expressed in various parts of the central nervous system, including the retina. The localization of the key eCB receptors, particularly CB1R and CB2R, has been recently reported in rodent and primate retinas with striking interspecies differences. Little is known about the distribution of the enzymes involved in the synthesis and degradation of these eCBs. We therefore examined the expression and localization of the main components of the eCB system in the retina of mice, tree shrews, and monkeys. We found that CB1R and FAAH distributions are well-preserved among these species. However, expression of NAPE-PLD is circumscribed to the photoreceptor layer only in monkeys. In contrast, CB2R expression is variable across these species; in mice, CB2R is found in retinal neurons but not in glial cells; in tree shrews, CB2R is expressed in Müller cell processes of the outer retina and in retinal neurons of the inner retina; in monkeys, CB2R is restricted to Müller cells. Finally, the expression patterns of MAGL and DAGLα are differently expressed across species. Overall, these results provide evidence that the eCB system is differently expressed in the retina of these mammals and suggest a distinctive role of eCBs in visual processing.
内源性大麻素（eCB）系统广泛表达于中枢神经系统的各个部位，包括视网膜。最近有报道称，在啮齿动物和灵长类动物的视网膜中，关键的eCB受体，特别是CB1R和CB2R的定位存在显著的种间差异。对于参与这些eCB合成和降解的酶的分布了解甚少。因此，我们研究了小鼠、树鼩和猴子视网膜中eCB系统主要成分的表达和定位。我们发现，CB1R和脂肪酸酰胺水解酶（FAAH）的分布在这些物种中保存良好。然而，N-酰基磷脂酰乙醇胺特异性磷脂酶D（NAPE-PLD）的表达仅在猴子的光感受器层中受到限制。相比之下，CB2R的表达在这些物种中存在差异；在小鼠中，CB2R存在于视网膜神经元中，但不存在于神经胶质细胞中；在树鼩中，CB2R在外视网膜的穆勒细胞突起和内视网膜的视网膜神经元中表达；在猴子中，CB2R仅限于穆勒细胞。最后，单酰甘油脂肪酶（MAGL）和二酰甘油脂肪酶α（DAGLα）的表达模式在不同物种中也有所不同。总体而言，这些结果提供了证据，表明eCB系统在这些哺乳动物的视网膜中表达不同，并暗示eCB在视觉处理中具有独特作用。
