Melanopsin-containing retinal. ganglion cells: Architecture, projections, and intrinsic photosensitivity
Melanopsin-containing retinal. ganglion cells: Architecture, projections, and intrinsic photosensitivity
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DOI：
10.1126/science.1069609
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发表时间：
2002-02-08
期刊：
影响因子：
56.9
通讯作者：
Yau, KW
中科院分区：
文献类型：
--
作者：
Hattar, S;Liao, HW;Yau, KW
哺乳动物大脑的视交叉上核（SCN）中的初级昼夜节律起搏器被来自眼睛的光信号通过视网膜下丘脑束所光携带。视网膜杆状细胞和锥状细胞不需要光掺杂。最近的证据表明，携带光感受器是投射到SCN的视网膜神经节细胞（RGCs）。这种光感受器的视觉色素可能是黑视素，一种类似于视蛋白的蛋白质，其编码信使RNA存在于哺乳动物RGCs的一个子集中。通过克隆大鼠黑视素并产生特异性抗体，我们发现黑视素存在于大鼠RGCs的细胞体、树突和近端轴突段。在针对黑视素基因位点的tau-lacZ杂合的小鼠中，p -半乳糖苷酶阳性的RGC轴突投射到SCN和其他参与昼夜光夹带或瞳孔光反射的脑核。表现出内在光敏性的大鼠RGCs总是表达黑视素。因此，黑视素很可能是光导RGCs的视觉色素，它设置生物钟并启动其他非图像形成的视觉功能。
The primary circadian pacemaker, in the suprachiasmatic nucleus (SCN) of the mammalian brain, is photoentrained by light signals from the eyes through the retinohypothalamic tract. Retinal rod and cone cells are not required for photoentrainment. Recent evidence suggests that the entraining photoreceptors are retinal ganglion cells (RGCs) that project to the SCN. The visual pigment for this photoreceptor may be melanopsin, an opsin-like protein whose coding messenger RNA is found in a subset of mammalian RGCs. By cloning rat melanopsin and generating specific antibodies, we show that melanopsin is present in cell bodies, dendrites, and proximal axonal segments of a subset of rat RGCs. In mice heterozygous for tau-lacZ targeted to the melanopsin gene locus, P-galactosidase-positive RGC axons projected to the SCN and other brain nuclei involved in circadian photoentrainment or the pupillary light reflex. Rat RGCs that exhibited intrinsic photosensitivity invariably expressed melanopsin. Hence, melanopsin is most likely the visual pigment of phototransducing RGCs that set the circadian clock and initiate other non-image-forming visual functions.