Melanopsin and inner retinal photoreception.
Over the last ten years there has been growing acceptance that retinal photoreception among mammals extends beyond rods and cones to include a small number of intrinsically photosensitive retinal ganglion cells (ipRGCs). These ipRGCs are capable of responding to light in the absence of rod/cone input thanks to expression of an opsin photopigment called melanopsin. They are specialised for measuring ambient levels of light (irradiance) for a wide variety of so-called non-image-forming light responses. These include synchronisation of circadian clocks to light:dark cycles and the regulation of pupil size, sleep propensity and pineal melatonin production. Here, we provide a review of some of the landmark discoveries in this fast developing field, paying particular emphasis to recent findings and key areas for future investigation.
Bailes
Helena J
HJ
Faculty of Life Sciences, The University of Manchester, Oxford Road, Manchester, M13 9PT, UK. helena.bailes@manchester.ac.uk
Lucas
Robert J
RJ
D000818:Animals; D002940:Circadian Rhythm / Q000502:physiology; D055537:Light Signal Transduction; D051379:Mice; D012160:Retina / Q000166:cytology / Q000378:metabolism / Q000502:physiology; D012165:Retinal Ganglion Cells / Q000166:cytology / Q000378:metabolism / Q000502:physiology*; D017299:Rod Opsins / Q000737:chemistry* / Q000378:metabolism; D000099210:Melanopsin
D017299:Rod Opsins; D000099210:Melanopsin