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An Expanding Role for Nonvisual Opsins in Extraocular Light Sensing Physiology
Mutahar Andrabi1,2, Brian A Upton1,2,3,4, Richard A Lang1,2,5,6
1The Visual Systems Group, Abrahamson Pediatric Eye Institute, Division of Pediatric Ophthalmology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA; email: richard.lang@cchmc.org, shruti.vemaraju@cchmc.org.
Annual Review of Vision Science
|May 17, 2023
Summary
Mammals can sense light outside of their eyes using opsins like encephalopsin (OPN3) and neuropsin (OPN5). These proteins regulate circadian rhythms and metabolism, challenging previous beliefs about mammalian light perception.
Area of Science:
- * Biology
- * Physiology
- * Neuroscience
Background:
- * Terrestrial life has evolved mechanisms to sense and utilize light.
- * Opsin proteins are key light sensors in animals, primarily known for vision.
- * Extraocular opsins mediate non-visual light sensing for seasonal behaviors and camouflage.
Purpose of the Study:
- * To review current findings on extraocular photoreception.
- * To highlight the roles of encephalopsin (OPN3) and neuropsin (OPN5) in mammals.
- * To discuss the relevance of these discoveries for human physiology.
Main Methods:
- * Review of existing scientific literature on opsins and extraocular light sensing.
- * Analysis of studies investigating OPN3 and OPN5 functions in model organisms.
- * Synthesis of evidence regarding the physiological impacts of non-visual light detection.
Main Results:
- * Mammals possess extraocular light-sensing capabilities, contrary to previous assumptions.
- * Encephalopsin (OPN3) and neuropsin (OPN5) mediate light sensing outside the eyes in mice.
- * These opsins regulate critical functions like circadian clock photoentrainment and metabolic pathways.
Conclusions:
- * Extraocular photoreception is a significant biological process in mammals.
- * OPN3 and OPN5 play crucial roles in non-visual light responses.
- * Understanding these mechanisms has implications for human health and physiology.
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