Department of Biological Sciences, Simon Fraser University, Burnaby, British Columbia, Canada.
Department of Biology, University of Victoria, Victoria, British Columbia, Canada.
J Comp Neurol. 2023 Jul;531(10):1080-1094. doi: 10.1002/cne.25482. Epub 2023 Apr 18.
Fishes experience different light environments over short time periods that may require quick modulation of photoreceptor properties to optimize visual function. Previous research has shown that the relative expression of different visual pigment protein (opsin) transcripts can change within several days following exposure to new light environments, but whether such changes are mirrored by analogous modulation in opsin protein expression is unknown. Here, Atlantic halibut larvae and juveniles raised under white light were exposed to blue light for 1 week and their retina compared to that of controls, which remained under white light. Blue light-treated larvae showed increased expression of all cone opsin transcripts, except rh2, over controls. They also had longer outer segments, and higher density of long wavelength sensitive (L) cones in the dorsal retina. In contrast, only the lws transcript was upregulated in juveniles exposed to blue light compared to controls but their L cone density was greater throughout the retina. These results demonstrate two mechanisms of rapid photoreceptor plasticity as a function of developmental stage associated with improved perception of achromatic or chromatic contrasts in line with the animal's ecological needs.
鱼类在短时间内经历不同的光照环境，这可能需要快速调节光感受器的特性以优化视觉功能。先前的研究表明，在暴露于新的光照环境后的几天内，不同视觉色素蛋白（视蛋白）转录本的相对表达可以发生变化，但这种变化是否与视蛋白蛋白表达的类似调节相匹配尚不清楚。在这里，在白光下饲养的大西洋比目鱼幼虫和幼鱼被暴露在蓝光下 1 周，然后将其视网膜与仍处于白光下的对照组进行比较。与对照组相比，蓝光处理的幼虫显示出所有视锥细胞视蛋白转录本的表达增加，除了 rh2。它们的外节也更长，在背侧视网膜中长波长敏感（L）锥体的密度更高。相比之下，只有 lws 转录本在暴露于蓝光的幼鱼中相对于对照组上调，但它们的 L 锥体密度在整个视网膜中都更大。这些结果表明，两种快速光感受器可塑性机制与动物的生态需求相关，与发育阶段有关，与对非彩色或彩色对比度的感知改善有关。
