Regulation of the circadian activity by melanopsin cells in ambient light conditions filtered to wavelengths below to 500 nm

Abstract

Purpose :To study the variations in the circadian activity in the mouse behaviour with diferent composition of the luminous spectra. Blue light has been identifed as one cause of retinal damage. Nevertheless, these wavelengths (400‐500nm) are important in the process of intrinsically photosensitive ganglion cells (ipRGCs) activation. These cells are essential in not forming images processes such as the pupillary refex, regulation of the circadian activity and/or release of melatonin. Further, ipRGCs are necessary and suficient to maintain the synchronization of endogenous cycles with circadian activity of each individual. Methods: By using Circadian Activity cages and diferent mouse models, we have investigated their behaviour when exposed to the entire light spectrum or to diferent amounts of the light‐filtered blue component. We have analyzed the behaviour of C57BL6J mice, which have all retinal photosensitive cells, and Rd10 mice, who comprise ipRGCs as the only photosensitive cells in their retinas by postnatal day 100. Results; The use of diverse mouse models has allowed us to investigate the contribution of diferent photoreceptor classes to the regulation of circadian activity in distinct light conditions. We have observed that ipRGCs are suficient to maintain the synchronization of endogenous cycles with circadian activity of each individual. Mouse behaviour changes depending on the amount of blue light. Conclusion: The maximum activation of melanopsin‐expressing cells is conditioned by the presence of filters for wavelengths below 500nm. Variations in behaviour exist depending on the amount of visible blue light filtered