A novel intrinsic electroretinogram response in isolated mouse retina
A novel intrinsic electroretinogram response in isolated mouse retina
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DOI：
10.1016/j.neuroscience.2017.06.021
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发表时间：
2017-08
期刊：
影响因子：
3.3
通讯作者：
M. Takao;Y. Fukuda;T. Morita
中科院分区：
文献类型：
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作者：
M. Takao;Y. Fukuda;T. Morita
自2002年发现视网膜内光敏神经节细胞（intrinsic photosensitive retinal ganglion cell，ipRGC）以来，人们对这种细胞的许多特征进行了描述。然而，关于直接反映ipRGC活性的视网膜造影成分的信息很少。在这项研究中，我们确定了视网膜电图（microERG），反映了ipRGCs inex小鼠视网膜的体内修复，其中经典的光感受器（视锥细胞和视杆细胞）被机械和光化学消融的光反应。MicroERG由三个部分组成：一个大的瞬态ON响应，一个小的和懒惰的驼峰19秒后的光，和一个大的瞬态OFF响应。完整的microERG记录需要至少30 s的曝光时间。MicroERG在478 nm处表现出最高的光谱光敏性。该波长对应于ipRGC的光敏曲线中的峰值波长。使用蓝色发光二极管（LED）光（470 nm）的心理物理测试显示，在ON和OFF响应中，microERG的绝对阈值照度均大于12.26 log photons/s/cm 2，而microERG不适应黑暗。microERG的振幅随光照强度的增加而线性增加。在microERG中，时间频率的敏感性高（至少100 Hz），如人类受试者中闪烁光对褪黑激素抑制的研究所表明的（Zelter等人，2014年）。褪黑激素的分泌被抑制光通过ipRGCs和视交叉上核。这些特性表明microERG可能反映了ipRGC在小鼠视网膜中作为亮度检测器的功能。
Since the discovery of intrinsic photosensitive retinal ganglion cell (ipRGC) was reported in 2002, many features specific to this cell type have been described. However, scare information is available on the retinographic components directly reflecting ipRGC activity. In this study, we identified the electroretinogram (microERG) that reflects the photoresponses by ipRGCs inex vivopreparations of the mouse retina, in which classical photoreceptors (cones and rods) were ablated mechanically and photochemically. MicroERG consisted of three components: a large transient ON response, a small and lazy hump 19 s after the onset of the light, and a large transient OFF response. A complete microERG recording required at least 30 s of light exposure. MicroERG showed the highest spectral photosensitivity at 478 nm. This wavelength corresponds to the peak wavelength in the ipRGCs’ photosensitive curve. The psychophysical test using a blue light-emitting diode (LED) light (470 nm) revealed that the absolute threshold illuminance for microERG was greater than 12.26 log photons/s/cm2in both ON and OFF responses, whereas microERG was not adapted for dark. The amplitude of microERG increased linearly with irradiance. The sensitivity of temporal frequency was high in microERG (at least 100 Hz), as suggested by the study on melatonin suppression by flickering light in human subjects (Zelter et al., 2014). Melatonin secretion was suppressed by light via ipRGCs and the suprachiasmatic nucleus. These properties of the photoresponse indicate that microERG may reflect the functions of ipRGC as a luminance detector in the mouse retina.