缺乏视杆视蛋白和视锥光感受器环核苷酸门控通道3α亚基的小鼠中的残余光敏感性。
Residual photosensitivity in mice lacking both rod opsin and cone photoreceptor cyclic nucleotide gated channel 3 alpha subunit.
作者信息
Barnard Alun R, Appleford Joanne M, Sekaran Sumathi, Chinthapalli Krishna, Jenkins Aaron, Seeliger Matheas, Biel Martin, Humphries Peter, Douglas Ron H, Wenzel Andreas, Foster Russell G, Hankins Mark W, Lucas Robert J
机构信息
Department of Integrative and Molecular Neuroscience, Division of Neuroscience and Psychological Medicine, Faculty of Medicine, Imperial College London, London, UK.
出版信息
Vis Neurosci. 2004 Sep-Oct;21(5):675-83. doi: 10.1017/S0952523804215024.
The mammalian retina contains three classes of photoreceptor. In addition to the rods and cones, a subset of retinal ganglion cells that express the putative sensory photopigment melanopsin are intrinsically photosensitive. Functional and anatomical studies suggest that these inner retinal photoreceptors provide light information for a number of non-image-forming light responses including photoentrainment of the circadian clock and the pupil light reflex. Here, we employ a newly developed mouse model bearing lesions of both rod and cone phototransduction cascades (Rho(-/-) Cnga3(-/-)) to further examine the function of these non-rod non-cone photoreceptors. Calcium imaging confirms the presence of inner retinal photoreceptors in Rho(-/-) Cnga3(-/-) mice. Moreover, these animals retain a pupil light reflex, photoentrainment, and light induction of the immediate early gene c-fos in the suprachiasmatic nuclei, consistent with previous findings that pupillary and circadian responses can employ inner retinal photoreceptors. Rho(-/-) Cnga3(-/-) mice also show a light-dependent increase in the number of FOS-positive cells in both the ganglion cell and (particularly) inner nuclear layers of the retina. The average number of cells affected is several times greater than the number of melanopsin-positive cells in the mouse retina, suggesting functional intercellular connections from these inner retinal photoreceptors within the retina. Finally, however, while we show that wild types exhibit an increase in heart rate upon light exposure, this response is absent in Rho(-/-) Cnga3(-/-) mice. Thus, it seems that non-rod non-cone photoreceptors can drive many, but not all, non-image-forming light responses.
哺乳动物的视网膜包含三类光感受器。除了视杆细胞和视锥细胞外,一部分表达假定的感光色素黑视蛋白的视网膜神经节细胞具有内在感光性。功能和解剖学研究表明,这些视网膜内层光感受器为许多非成像光反应提供光信息,包括昼夜节律时钟的光调节和瞳孔光反射。在这里,我们采用一种新开发的小鼠模型,该模型的视杆细胞和视锥细胞光转导级联均有损伤(Rho(-/-) Cnga3(-/-)),以进一步研究这些非视杆非视锥光感受器的功能。钙成像证实了Rho(-/-) Cnga3(-/-)小鼠视网膜内层存在光感受器。此外,这些动物保留了瞳孔光反射、光调节以及视交叉上核中即时早期基因c-fos的光诱导,这与之前瞳孔和昼夜节律反应可利用视网膜内层光感受器的发现一致。Rho(-/-) Cnga3(-/-)小鼠在视网膜神经节细胞层和(尤其是)内核层中FOS阳性细胞的数量也呈现出光依赖性增加。受影响细胞的平均数量比小鼠视网膜中黑视蛋白阳性细胞的数量大几倍,这表明这些视网膜内层光感受器在视网膜内存在功能性细胞间连接。然而,最后,虽然我们发现野生型小鼠在光照下心率会增加,但Rho(-/-) Cnga3(-/-)小鼠没有这种反应。因此,非视杆非视锥光感受器似乎可以驱动许多但并非所有的非成像光反应。