Modulations in irradiance directed at melanopsin, but not cone photoreceptors, reliably alter electrophysiological activity in the suprachiasmatic nucleus and circadian behaviour in mice.
Modulations in irradiance directed at melanopsin, but not cone photoreceptors, reliably alter electrophysiological activity in the suprachiasmatic nucleus and circadian behaviour in mice.
复制标题
针对黑视蛋白而不是视锥细胞的辐照度调节可靠地改变了小鼠视交叉上核的电生理活动和昼夜节律行为。
DOI：
10.1111/jpi.12735
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发表时间：
2021
影响因子：
10.3
通讯作者：
Mouland JW
中科院分区：
文献类型：
--
作者：
Mouland JW
视网膜内光敏神经节细胞将内在的、基于黑视蛋白的光感受信号与视杆细胞和视锥细胞产生的光感受信号一起传递到视交叉上核（SCN）昼夜节律钟。迄今为止，实验数据表明，黑视蛋白在测量环境光强度方面比视锥光感受起着更重要的作用。此类研究绝大多数使用漫射光刺激，而我们周围世界的光强度会随着空间和时间的变化而变化。在这里，我们调查了黑视蛋白或视锥信号在何种程度上支持昼夜节律的辐照度测量中存在的自然时空变化的光强度。为了解决这个问题，我们首先向麻醉的小鼠呈现高对比度和低对比度电影，同时记录SCN的细胞外电生理活动。使用具有改变的视锥敏感性的小鼠系（Opn1mwR小鼠）和多光谱光源，然后我们选择性地改变特定感光器类别的电影的辐照度。我们发现，黑视辐照度的步骤在很大程度上解释了在起始光强度范围内和存在时空调制的情况下SCN活性的光诱导变化。相比之下，当时空对比度较低时，锥定向的辐照度变化仅影响SCN活性。与这些发现一致，在我们可以独立调节黑视蛋白与视锥的辐照度的住房条件下，恒定光对行为中的昼夜节律的周期延长效应由黑视辐照度可靠地确定，而不管视锥的辐照度。这些数据增加了越来越多的证据，即调节黑视蛋白的有效辐照度是控制光的昼夜节律影响的有效策略。
Intrinsically photosensitive retinal ganglion cells convey intrinsic, melanopsin‐based, photoreceptive signals alongside those produced by rods and cones to the suprachiasmatic nucleus (SCN) circadian clock. To date, experimental data suggest that melanopsin plays a more significant role in measuring ambient light intensity than cone photoreception. Such studies have overwhelmingly used diffuse light stimuli, whereas light intensity in the world around us varies across space and time. Here, we investigated the extent to which melanopsin or cone signals support circadian irradiance measurements in the presence of naturalistic spatiotemporal variations in light intensity. To address this, we first presented high‐ and low‐contrast movies to anaesthetised mice whilst recording extracellular electrophysiological activity from the SCN. Using a mouse line with altered cone sensitivity (Opn1mwRmice) and multispectral light sources we then selectively varied irradiance of the movies for specific photoreceptor classes. We found that steps in melanopic irradiance largely account for the light induced‐changes in SCN activity over a range of starting light intensities and in the presence of spatiotemporal modulation. By contrast, cone‐directed changes in irradiance only influenced SCN activity when spatiotemporal contrast was low. Consistent with these findings, under housing conditions where we could independently adjust irradiance for melanopsin versus cones, the period lengthening effects of constant light on circadian rhythms in behaviour were reliably determined by melanopic irradiance, regardless of irradiance for cones. These data add to the growing evidence that modulating effective irradiance for melanopsin is an effective strategy for controlling the circadian impact of light.