1. Beyond Lux: methods for species and photoreceptor-specific quantification of ambient light for mammals.
- Author
-
McDowell RJ, Didikoglu A, Woelders T, Gatt MJ, Moffatt F, Notash S, Hut RA, Brown TM, and Lucas RJ
- Subjects
- Animals, Photoreceptor Cells, Vertebrate physiology, Mice physiology, Rod Opsins metabolism, Humans, Light, Mammals physiology, Species Specificity
- Abstract
Background: Light is a key environmental regulator of physiology and behaviour. Mistimed or insufficient light disrupts circadian rhythms and is associated with impaired health and well-being across mammals. Appropriate lighting is therefore crucial for indoor housed mammals. Light is commonly measured in lux. However, this employs a spectral weighting function for human luminance and is not suitable for 'non-visual' effects of light or use across species. In humans, a photoreceptor-specific (α-opic) metrology system has been proposed as a more appropriate way of measuring light., Results: Here we establish technology to allow this α-opic measurement approach to be readily extended across mammalian species, accounting for differences in photoreceptor types, photopigment spectral sensitivities, and eye anatomy. We develop a high-throughput method to derive spectral sensitivities for recombinantly expressed mammalian opsins and use it to establish the spectral sensitivity of melanopsin from 13 non-human mammals. We further address the need for simple measurement strategies for species-specific α-opic measures by developing an accessible online toolbox for calculating these units and validating an open hardware multichannel light sensor for 'point and click' measurement. We finally demonstrate that species-specific α-opic measurements are superior to photopic lux as predictors of physiological responses to light in mice and allow ecologically relevant comparisons of photosensitivity between species., Conclusions: Our study presents methods for measuring light in species-specific α-opic units that are superior to the existing unit of photopic lux and holds the promise of improvements to the health and welfare of animals, scientific research reproducibility, agricultural productivity, and energy usage., Competing Interests: Declarations Ethics approval and consent to participate Transmission data was collected under the University of Groningen Animal Experiments Committee licence number BG02197/98. Consent for publication Not applicable. Competing interests RJL and TMB have received investigator-initiated grant funding from Signify/Philips Lighting and RJL has received honoraria from Samsung Electronics. RJL received financial support from NASA, UFAW (11–22/23), the Commission International de l’Eclairage and the University of Manchester to organise a workshop about the measurement of species-specific light units for laboratory mammals (Manchester, 2023)., (© 2024. The Author(s).)
- Published
- 2024
- Full Text
- View/download PDF