Resumen:
hroughout evolution, the need to detect light has generated highly specialized photoreceptor cells that in vertebrates are mainly located in the retina. The most studied photodetectors within these cells are the visual photoreceptors "cones and rods" responsible for day and night vision, respectively. These cells contain photosensitive molecules consisting of a protein part called ?opsin? that binds a chromophore derived from vitamin A, retinaldehyde, capable of photoisomerizing from 11-cis retinal to all-trans retinal form, and triggering the light responses that lead to vision. However, other cells of the inner retina of vertebrates (retinal ganglion cells (RGCs), horizontal cells (HCs), and Muller´s glial cells) are currently known to express non-visual photopigments such as melanopsin (Opn4), encephalopsin (Opn3 ) and neuropsin (Opn5), which would be involved in diverse functions not associated with imaging. Melanopsin is the most widely studied of them, it is expressed in intrins