Differential cone pathway influence on intrinsically photosensitive retinal ganglion cell subtypes.
Differential cone pathway influence on intrinsically photosensitive retinal ganglion cell subtypes.
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DOI：
10.1523/jneurosci.3656-10.2010
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发表时间：
2010-12-01
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影响因子：
--
通讯作者：
Kofuji P
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文献类型：
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作者：
Schmidt TM;Kofuji P
哺乳动物视网膜中的一小部分神经节细胞表达色素黑视蛋白并且是固有光敏的（ipRGC）。这些细胞是光信息传递到非图像形成视觉中心的主要管道，非图像形成视觉中心介导诸如瞳孔光反射和昼夜变化的行为。M1和M2细胞包括ipRGC的不同形态亚群，并且在其内在膜特性和内在光响应方面具有生理多样性。此外，现在有证据表明，所有ipRGC通过突触信号传导从视杆/视锥接收光信息。最近有报道称，Off-stratifying M1细胞自相矛盾地接收来自内丛状层的Off亚层内的On通路的输入。本研究的目的是检查视锥细胞通路信号传导到M1和M2细胞的功能后果。使用药理学工具和单细胞记录野生型和黑视素缺失小鼠的突触反应，我们发现，在通路形成的主要兴奋性突触输入M1和M2细胞。这种输入在塑造M2细胞的光诱发反应和静息膜特性方面比M1细胞更有影响力。这些发现表明ipRGC亚群对视锥介导的光转导的惊人差异依赖。这些发现还表明ipRGC亚型向各种非图像形成视觉中心发出不同的光信息。
A small subset of ganglion cells in the mammalian retina express the photopigment melanopsin and are intrinsically photosensitive (ipRGCs). These cells are the primary conduits through which photic information is relayed to non-image forming visual centers that mediate behaviors such as the pupillary light reflex and circadian entrainment. M1 and M2 cells comprise distinct morphological subpopulations of ipRGC, and possess physiological diversity in their intrinsic membrane properties and intrinsic light responses. Additionally, evidence now indicates that all ipRGCs receive photic information from rods/cones via synaptic signaling. It has recently been reported that Off-stratifying M1 cells paradoxically receive input from the On pathway within the Off sublamina of the inner plexiform layer. The purpose of the current study was to examine the functional consequences of cone pathway signaling to M1 and M2 cells. Using pharmacological tools and single-cell recordings of synaptic responses in wild-type and melanopsin-null mice, we found that the On pathway forms the primary excitatory synaptic input to both M1 and M2 cells. This input was much more influential in shaping the light-evoked responses and resting membrane properties of M2 cells than M1 cells. These findings indicate a surprising differential reliance upon cone-mediated phototransduction by ipRGC subpopulations. These findings also suggest that ipRGC subtypes signal diverse photic information to various non-image forming visual centers.