Howard, RBKniller, JBolstad, KSRAcosta, ML2026-05-202026-05-202024-04-25Vision, ISSN: 2411-5150 (Print); 2411-5150 (Online), MDPI AG, 8(2), 26-. doi: 10.3390/vision80200262411-51502411-5150http://hdl.handle.net/10292/21138The outward migration of ommin pigment granules from the bases to the tips of the photoreceptors in response to light has been reported in the retina of several (mostly coastal) squid species. Following exposure to light and then dark conditions, we collected and processed retinal tissue from juvenile specimens of a deep-sea oegopsid squid, Gonatus onyx. We aimed to determine whether the ommin pigment returns to baseline, and to investigate the presence of glutamate neurotransmitter signaling under both dark and light conditions. We confirmed the presence of ommin granules but observed variability in the return of pigment to the basal layer in dark conditions, as well as changes in glutamate distribution. These findings provide support for the migration of retinal ommin pigment granules as a mechanism for regulating incoming light.© 2024 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/).https://creativecommons.org/licenses/by/4.0/cephalopodneurotransmittersomminpigment migrationretinasquidvision32 Biomedical and Clinical Sciences3212 Ophthalmology and OptometryEye Disease and Disorders of VisionNeurosciences3212 Ophthalmology and optometry5204 Cognitive and computational psychologyJournal ArticleOpenAccess10.3390/vision8020026