Leibrock C S, Reuter T, Lamb T D
Department of Physiology, University of Cambridge, UK.
Eye (Lond). 1998;12 ( Pt 3b):511-20. doi: 10.1038/eye.1998.139.
Following exposure of the eye to an intense light that 'bleaches' a significant fraction of the rhodopsin, one's visual threshold is initially greatly elevated, and takes tens of minutes to recover to normal. The elevation of visual threshold arises from events occurring within the rod photoreceptors, and the underlying molecular basis of these events and of the rod's recovery is now becoming clearer. Results obtained by exposing isolated toad rods to hydroxylamine solution indicate that, following small bleaches, the primary intermediate causing elevation of visual threshold is metarhodopsin II, in its phosphorylated and arrestin-bound form. This product activates transduction with an efficacy about 100 times greater than that of opsin.
眼睛暴露于强光下会使相当一部分视紫红质“漂白”，此时人的视觉阈值最初会大幅升高，需要数十分钟才能恢复正常。视觉阈值的升高源于视杆光感受器内发生的事件，这些事件以及视杆恢复的潜在分子基础现在正变得越来越清晰。将分离的蟾蜍视杆暴露于羟胺溶液中所获得的结果表明，在小剂量漂白后，导致视觉阈值升高的主要中间体是磷酸化且与抑制蛋白结合的视紫红质II。该产物激活转导的效率比视蛋白高约100倍。
