Chromophore regeneration: Melanopsin does its own thing

摘要

Among the most surprising findings in visual science of the last decade has been that photore-ception in the mammalian retina is not restricted to the rods and cones, but extends to a small number of cells in the inner retina. These new photoreceptors, which comprise a small subset of retinal ganglion cells, are capable of driving a number of "non-image-forming" light responses including circadian photoen-trainment and the regulation of pupil size even in the absence of functional rods and cones. The so-called intrinsically photosensitive retinal ganglion cells (ipRGCs) absorb light through an opsin/ retinaldehyde-based photopigment called melanopsin.