Light adaptation characteristics of melanopsin
|
Accepted Version
(PDF 1MB)
98312968. Available under License Creative Commons Attribution Non-commercial No Derivatives 4.0. |
Free-to-read version at publisher website
Description
Following photopigment bleaching, the rhodopsin and cone-opsins show a characteristic exponential regeneration in the dark with a photocycle dependent on the retinal pigment epithelium. Melanopsin pigment regeneration in animal models requires different pathways to rods and cones. To quantify melanopsin-mediated light adaptation in humans, we first estimated its photopigment regeneration kinetics through the photo-bleach recovery of the intrinsic melanopsin pupil light response (PLR). An intense broadband light (~120,000 Td) bleached 43% of melanopsin compared to 86% of the cone-opsins. Recovery from a 43% bleach was 3.4X slower for the melanopsin than cone-opsin. Post-bleach melanopsin regeneration followed an exponential growth with a 2.5 min time-constant (τ) that required 11.2 min for complete recovery; the half-bleaching level (Ip) was ~ 4.47 log melanopic Td (16.10 log melanopsin effective photons.cm−2.s−1; 8.25 log photoisomerisations.photoreceptor−1.s−1). The effect on the cone-directed PLR of the level of the melanopsin excitation during continuous light adaptation was then determined. We observed that cone-directed pupil constriction amplitudes increased by ~ 10% when adapting lights had a higher melanopic excitation but the same mean photometric luminance. Our findings suggest that melanopsin light adaptation enhances cone signalling along the non-visual retina-brain axis. Parameters τ and Ip will allow estimation of the level of melanopsin bleaching in any light units; the data have implications for quantifying the relative contributions of putative melanopsin pathways to regulate the post-bleach photopigment regeneration and adaptation.
Impact and interest:
Citation counts are sourced monthly from Scopus and Web of Science® citation databases.
These databases contain citations from different subsets of available publications and different time periods and thus the citation count from each is usually different. Some works are not in either database and no count is displayed. Scopus includes citations from articles published in 1996 onwards, and Web of Science® generally from 1980 onwards.
Citations counts from the Google Scholar™ indexing service can be viewed at the linked Google Scholar™ search.
Full-text downloads:
Full-text downloads displays the total number of times this work’s files (e.g., a PDF) have been downloaded from QUT ePrints as well as the number of downloads in the previous 365 days. The count includes downloads for all files if a work has more than one.
ID Code: | 213269 | ||||||
---|---|---|---|---|---|---|---|
Item Type: | Contribution to Journal (Journal Article) | ||||||
Refereed: | Yes | ||||||
ORCID iD: |
|
||||||
Additional Information: | Funding Information: Supported by the Australian Research Council Discovery Projects ARC-DP170100274 (AJZ, BF) and an Australian Research Council Future Fellowship ARC-FT180100458 (AJZ). We thank Dingcai Cao and Drew Carter for photostimulator and software development. | ||||||
Measurements or Duration: | 13 pages | ||||||
Keywords: | Dark adaptation, Light adaptation, Melanopsin, Photopigment bleaching, Photopigment regeneration, Pupil light response | ||||||
DOI: | 10.1016/j.visres.2021.07.005 | ||||||
ISSN: | 0042-6989 | ||||||
Pure ID: | 98312968 | ||||||
Divisions: | Current > Research Centres > Centre for Vision and Eye Research Current > QUT Faculties and Divisions > Faculty of Health Current > Schools > School of Biomedical Sciences Current > Schools > School of Optometry & Vision Science |
||||||
Funding Information: | Supported by the Australian Research Council Discovery Projects ARC-DP170100274 (AJZ, BF) and an Australian Research Council Future Fellowship ARC-FT180100458 (AJZ). We thank Dingcai Cao and Drew Carter for photostimulator and software development. | ||||||
Funding: | |||||||
Copyright Owner: | 2021 Elsevier Ltd | ||||||
Copyright Statement: | This work is covered by copyright. Unless the document is being made available under a Creative Commons Licence, you must assume that re-use is limited to personal use and that permission from the copyright owner must be obtained for all other uses. If the document is available under a Creative Commons License (or other specified license) then refer to the Licence for details of permitted re-use. It is a condition of access that users recognise and abide by the legal requirements associated with these rights. If you believe that this work infringes copyright please provide details by email to qut.copyright@qut.edu.au | ||||||
Deposited On: | 14 Sep 2021 04:04 | ||||||
Last Modified: | 16 Jun 2024 18:17 |
Export: EndNote | Dublin Core | BibTeX
Repository Staff Only: item control page