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.
Faculty of Life Sciences, The University of Manchester, Oxford Road, Manchester, M13 9PT, UK. helena.bailes@manchester.ac.uk
Helena J
HJ
Bailes
Robert J
RJ
Lucas
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