用视网膜电图在体内跟踪人类视网膜暗适应：洞察视锥细胞和视杆细胞介导的视觉恢复过程,The Journal of Physiology

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用视网膜电图在体内跟踪人类视网膜暗适应：洞察视锥细胞和视杆细胞介导的视觉恢复过程
The Journal of Physiology ( IF 4.7 ) Pub Date : 2022-05-25 , DOI: 10.1113/jp283105
Xiaofan Jiang _{1,

2,

3,

4} , Omar A Mahroo _{1,

2,

3,

4,

5}

Affiliation

一个多世纪以来，人们一直在研究漂白暴露后恢复视觉敏感度（暗适应）所需的大量时间。心理物理学研究产生了经典的双相曲线，代表锥体驱动和杆驱动视觉的恢复。视网膜电图 (ERG) 允许直接评估视网膜水平（光感受器、双极细胞）的恢复，70 多年前的第一份报告。在过去的二十年里，暗适应的 ERG 研究已经深入了解了潜在的生理过程。大漂白后，杆状光感受器循环电流，从杆状隔离的明亮闪光 ERG a 波估计，需要 30 分钟才能恢复，表明漂白产物被认为是游离视蛋白（未结合到 11-顺式-视网膜), 继续激活光转导, 关闭杆循环电流。相比之下，用锥形驱动的明亮闪光 ERG a 波评估的锥形电流在类似暴露后 100 毫秒内恢复，表明游离视蛋白无法关闭锥形电流。锥形驱动暗淡闪光 a 波可用于跟踪锥形光色素的恢复，表明再生是“速率受限”的，而不是一阶的。暗淡闪光 ERG b 波的恢复也与限速杆状光色素再生一致（其中游离视蛋白，使视觉系统脱敏为“等效背景”，通过限速递送 11- cis去除-视网膜）。这些发现与心理物理学和视网膜密度测量研究一致，尽管存在无法解释的分歧点。已经在年龄相关性黄斑变性和视网膜疾病视觉周期抑制剂试验中探索了漂白后 ERG 恢复。暗适应的 ERG 跟踪可能在未来的临床环境中被证明是有用的。

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Human retinal dark adaptation tracked in vivo with the electroretinogram: insights into processes underlying recovery of cone- and rod-mediated vision

The substantial time taken for regaining visual sensitivity (dark adaptation) following bleaching exposures has been investigated for over a century. Psychophysical studies yielded the classic biphasic curve representing recovery of cone-driven and rod-driven vision. The electroretinogram (ERG) permits direct assessment of recovery at the level of the retina (photoreceptors, bipolar cells), with the first report over 70 years ago. Over the last two decades, ERG studies of dark adaptation have generated insights into underlying physiological processes. After large bleaches, rod photoreceptor circulating current, estimated from the rod-isolated bright-flash ERG a-wave, takes 30 min to recover, indicating that products of bleaching, thought to be free opsin (unbound to 11-cis-retinal), continue to activate phototransduction, shutting off rod circulating current. In contrast, cone current, assessed with cone-driven bright-flash ERG a-waves, recovers within 100 ms following similar exposures, suggesting that free opsin is less able to shut off cone current. The cone-driven dim-flash a-wave can be used to track recovery of cone photopigment, showing regeneration is 'rate-limited' rather than first order. Recoveries of the dim-flash ERG b-wave are consistent also with rate-limited rod photopigment regeneration (where free opsin, desensitising the visual system as an 'equivalent background', is removed by rate-limited delivery of 11-cis-retinal). These findings agree with psychophysical and retinal densitometry studies, although there are unexplained points of divergence. Post-bleach ERG recovery has been explored in age-related macular degeneration and in trials of visual cycle inhibitors for retinal diseases. ERG tracking of dark adaptation may prove useful in future clinical contexts.

更新日期：2022-05-25

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