Pepperberg D R, Lurie M, Brown P K, Dowling J E
Science. 1976 Jan 30;191(4225):394-6. doi: 10.1126/science.1246621.
Incubation with externally applied 11-cis retinal induces a marked increase of visual sensitivity within partially bleached skate photoreceptors. This activity of 11-cis retinal is duplicated by 9-cis retinal, but not by all-trans retinal. The sensitization of photoreceptors promoted by 11-cis and 9-cis retinal is accompanied by the formation of rhodopsin and isorhodopsin, respectively.