Melanopsin Phototransduction Is Repurposed by ipRGC Subtypes to Shape the Function of Distinct Visual Circuits.
Melanopsin Phototransduction Is Repurposed by ipRGC Subtypes to Shape the Function of Distinct Visual Circuits.
复制标题
DOI：
10.1016/j.neuron.2018.06.032
复制
发表时间：
2018-08-22
期刊：
影响因子：
16.2
通讯作者：
Schmidt TM
中科院分区：
文献类型：
--
作者：
Sonoda T;Lee SK;Birnbaumer L;Schmidt TM
黑视素在不同类型的内在光敏视网膜神经节细胞（ipRGCs）中表达，这些细胞驱动从昼夜光干扰到对比度检测的行为。一个悬而未决的主要问题是，同样的光色素黑视素如何影响如此截然不同的功能。本研究表明，黑视素在对比度检测中的作用始于视网膜，通过对M4 ipRGC （on α RGC）信号的直接影响。这种影响在从星光到太阳光的环境光水平范围内持续存在，这大大扩展了黑视素在视觉处理中的功能范围。此外，黑视素通过关闭钾泄漏通道增加M4 iprgc的兴奋性，钾泄漏通道是黑视素光传导级联的一个先前未被发现的靶点。引人注目的是，这种机制对于图像形成回路是选择性的，因为M1 iprgc（参与非图像形成行为）表现出黑视素介导的兴奋性降低。因此，黑视素信号被ipRGC亚型重新利用来塑造不同的视觉行为。Sonoda等人发现泄漏钾通道是M4 iprgc /ON α视网膜神经节细胞中黑视素光导的主要靶点。这些通道的黑视素依赖性关闭增强了细胞的兴奋性和在大范围光强度下的对比敏感性。
Melanopsin is expressed in distinct types of intrinsically photosensitive retinal ganglion cells (ipRGCs), which drive behaviors from circadian photoentrainment to contrast detection. A major unanswered question is how the same photopigment, melanopsin, influences such vastly different functions. Here we show that melanopsin’s role in contrast detection begins in the retina, via direct effects on M4 ipRGC (ON alpha RGC) signaling. This influence persists across an unexpectedly wide range of environmental light levels ranging from starlight to sunlight, which considerably expands the functional reach of melanopsin on visual processing. Moreover, melanopsin increases the excitability of M4 ipRGCs via closure of potassium leak channels, a previously unidentified target of the melanopsin phototransduction cascade. Strikingly, this mechanism is selective for image-forming circuits, as M1 ipRGCs (involved in non-image forming behaviors), exhibit a melanopsin-mediated decrease in excitability. Thus, melanopsin signaling is repurposed by ipRGC subtypes to shape distinct visual behaviors. Sonoda et al. identify leak potassium channels as the major target of melanopsin phototransduction in M4 ipRGCs/ON alpha retinal ganglion cells. Melanopsin-dependent closure of these channels enhances cell excitability and contrast sensitivity across a wide range of light intensities.
登录
查看更多内容
影响因子：
5.5
作者：
Bista, Pawan;Pawlowski, Matthias;Budde, Thomas
通讯作者：
Budde, Thomas
影响因子：
5.3
作者：
Hartwick, Andrew T. E.;Bramley, Jayne R.;Pickard, Gary E.
通讯作者：
Pickard, Gary E.
影响因子：
11.4
作者：
Chemin, J;Girard, C;Lazdunski, M
通讯作者：
Lazdunski, M
影响因子：
2.5
作者：
Hu, Caiping;Hill, DiJon D.;Wong, Kwoon Y.
通讯作者：
Wong, Kwoon Y.
影响因子：
8.8
作者：
Emanuel, Alan J.;Kapur, Kush;Do, Michael Tri H.
通讯作者：
Do, Michael Tri H.