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Melanopsin

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https://www.readbyqxmd.com/read/27914990/presence-of-melanopsin-in-human-crystalline-lens-epithelial-cells-and-its-role-in-melatonin-synthesis
#1
Hanan Awad Alkozi, Xiaoyu Wang, Maria Jesus Perez de Lara, Jesus Pintor
Melanopsin is a non-image forming photoreceptor known to be present in the retina and it is considered to have light regulated tasks among other functions. In the present work, melanopsin presence in human lens epithelial cells as well as in human lens tissue is described for the first time. Moreover, studying the concentration of melatonin and its synthesising enzyme AANAT proved a clear link between melanopsin activation and the suppression of melatonin synthesis. Melanopsin sensitivity to specific wavelength (465-480 nm, blue) was confirmed after making temporal studies incubating lens epithelial cells under light, red, green, blue and total darkness for 2, 4, 8, 12 h and analysing the concentration of both melatonin and its synthesising enzyme AANAT, discovering that melatonin levels after submitting cells to total darkness are significantly higher to ones submitted to white or specifically blue light (***p < 0...
November 30, 2016: Experimental Eye Research
https://www.readbyqxmd.com/read/27899883/commentary-melanopsin-regulates-both-sleep-promoting-and-arousal-promoting-responses-to-light
#2
COMMENT
Christian Cajochen, Sarah L Chellappa
No abstract text is available yet for this article.
2016: Frontiers in Neural Circuits
https://www.readbyqxmd.com/read/27893096/chemogenetic-activation-of-iprgcs-drives-changes-in-dark-adapted-scotopic-electroretinogram
#3
Nina Milosavljevic, Annette E Allen, Jasmina Cehajic-Kapetanovic, Robert J Lucas
Purpose: The purpose of this study was to investigate the impact of activating melanopsin-expressing intrinsically photosensitive retinal ganglion cells (ipRGCs) on dark-adapted (scotopic) electroretinograms (ERG). Methods: We used mice (Opn4Cre/+) expressing cre recombinase in melanopsin-expressing cells for a targeted gene delivery of a chemogenetic Gq-coupled receptor, hM3Dq, to ipRGCs. Intraperitoneal injection of clozapine N-oxide (CNO) at 5 mg/kg was used for acute activation of hM3Dq and thus excitation of ipRGCs in darkness...
November 1, 2016: Investigative Ophthalmology & Visual Science
https://www.readbyqxmd.com/read/27824104/degeneration-and-energy-shortage-in-the-suprachiasmatic-nucleus-underlies-the-circadian-rhythm-disturbance-in-apoe-mice-implications-for-alzheimer-s-disease
#4
Lan Zhou, Qian Gao, Meng Nie, Jing-Li Gu, Wei Hao, Lin Wang, Ji-Min Cao
Alzheimer's disease (AD) patients suffer sleep disorders and circadian rhythm disturbances (CRDs). The underlying mechanisms are incompletely understood, and treatments are lacking. In this study, we characterized the locomotor activity, clock gene expression, morphological degeneration and energy metabolism of suprachiasmatic nucleus (SCN), together with retinal light sensing, in ApoE(-/-) mice, a model for AD. Compared with the control C57BL/6J mice, ApoE(-/-) mice exhibited disordered circadian locomotor activity under dim light and constant darkness, with impaired re-entrainment to phase change schedules...
November 8, 2016: Scientific Reports
https://www.readbyqxmd.com/read/27821359/pupillary-response-abnormalities-in-depressive-disorders
#5
Scott A Laurenzo, Randy Kardon, Johannes Ledolter, Pieter Poolman, Ashley M Schumacher, James B Potash, Jan M Full, Olivia Rice, Anna Ketcham, Cole Starkey, Jess G Fiedorowicz
Depressive disorders lack objective physiological measurements to characterize the affected population and facilitate study of relevant mechanisms. The melanopsin-mediated light signaling pathway may contribute to seasonal variation and can be measured non-invasively by pupillometry. We prospectively studied changes in melanopsin-mediated pupillary constriction in 19 participants with major depressive disorder (MDD) and 10 control across the summer and winter solstices. The melanopsin-mediated response, as measured by the pupil's sustained constriction six s after a high intensity blue light stimulus, was marginally attenuated in those with MDD relative to controls (p=0...
October 21, 2016: Psychiatry Research
https://www.readbyqxmd.com/read/27789727/horizontal-cells-expressing-melanopsin-x-are-novel-photoreceptors-in-the-avian-inner-retina
#6
Luis P Morera, Nicolás M Díaz, Mario E Guido
In the vertebrate retina, three types of photoreceptors-visual photoreceptor cones and rods and the intrinsically photosensitive retinal ganglion cells (ipRGCs)-converged through evolution to detect light and regulate image- and nonimage-forming activities such as photic entrainment of circadian rhythms, pupillary light reflexes, etc. ipRGCs express the nonvisual photopigment melanopsin (OPN4), encoded by two genes: the Xenopus (Opn4x) and mammalian (Opn4m) orthologs. In the chicken retina, both OPN4 proteins are found in ipRGCs, and Opn4x is also present in retinal horizontal cells (HCs), which connect with visual photoreceptors...
November 15, 2016: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/27786307/coupling-optogenetic-stimulation-with-nanoluc-based-luminescence-bret-ca-sensing
#7
Jie Yang, Derrick Cumberbatch, Samuel Centanni, Shu-Qun Shi, Danny Winder, Donna Webb, Carl Hirschie Johnson
Optogenetic techniques allow intracellular manipulation of Ca(++) by illumination of light-absorbing probe molecules such as channelrhodopsins and melanopsins. The consequences of optogenetic stimulation would optimally be recorded by non-invasive optical methods. However, most current optical methods for monitoring Ca(++) levels are based on fluorescence excitation that can cause unwanted stimulation of the optogenetic probe and other undesirable effects such as tissue autofluorescence. Luminescence is an alternate optical technology that avoids the problems associated with fluorescence...
October 27, 2016: Nature Communications
https://www.readbyqxmd.com/read/27784072/the-effects-of-short-term-light-adaptation-on-the-human-post-illumination-pupil-response
#8
Daniel S Joyce, Beatrix Feigl, Andrew J Zele
Purpose: We determine the effect of short-term light adaptation on the pupil light reflex and the melanopsin mediated post-illumination pupil response (PIPR). Inner and outer retinal photoreceptor contributions to the dark-adapted pupil response were estimated. Methods: In Experiment A, light adaptation was studied using short wavelength lights ranging from subthreshold to suprathreshold irradiances for melanopsin signaling that were presented before (5-60 seconds) and after (30 seconds) a melanopsin-exciting stimulus pulse...
October 1, 2016: Investigative Ophthalmology & Visual Science
https://www.readbyqxmd.com/read/27727394/melanopsin-phototransduction-contributes-to-light-evoked-choroidal-expansion-and-rod-l-type-calcium-channel-function-in-vivo
#9
Bruce A Berkowitz, Tiffany Schmidt, Robert H Podolsky, Robin Roberts
Purpose: In humans, rodents, and pigeons, the dark → light transition signals nonretinal brain tissue to increase choroidal thickness, a major control element of choroidal blood flow, and thus of photoreceptor and retinal pigment epithelium function. However, it is unclear which photopigments in the retina relay the light signal to the brain. Here, we test the hypothesis that melanopsin (Opn4)-regulated phototransduction modulates light-evoked choroidal thickness expansion in mice. Methods: Two-month-old C57Bl/6 wild-type (B6), 4- to 5-month-old C57Bl/6/129S6 wild-type (B6 + S6), and 2-month-old melanopsin knockout (Opn4-/-) on a B6 + S6 background were studied...
October 1, 2016: Investigative Ophthalmology & Visual Science
https://www.readbyqxmd.com/read/27717718/ovarian-steroid-withdrawal-results-in-gabaa-receptor-upregulation-in-the-photoperiodic-neuroendocrine-pathways-of-the-turkey-hen
#10
Voravasa Chaiworakul, Sunantha Kosonsiriluk, Laura J Mauro, Mohamed E El Halawani
The mechanism(s) underlying photorefractoriness in temperate zone seasonally breeding birds remains undetermined. Our recent findings reveal a link between the upregulation of GABAA receptors (GABAARs) in the premammillary nucleus (PMM) and the state of photorefractoriness. Gonadal steroid levels fluctuate during the breeding season; increasing after gonadal recrudescence and declining sharply once gonadal regression begins. Here, we examined the effect of gonadal steroid withdrawal on the expression of GABAARs in the turkey PMM...
January 1, 2017: General and Comparative Endocrinology
https://www.readbyqxmd.com/read/27716445/suppression-of-vagal-cardiac-modulation-by-blue-light-in-healthy-subjects
#11
Emi Yuda, Hiroki Ogasawara, Yutaka Yoshida, Junichiro Hayano
BACKGROUND: In the contemporary life environments, our body is increasingly exposed to various sources of colored light, which may affect our physiological functions as non-image-forming effects. We examined the impacts of colored lights on the autonomic functions by the analysis of heart rate variability (HRV). METHODS: A lighting device consisting of four organic light-emitting diode (OLED) modules (55 × 55 mm(2)) with adjustable red-green-blue color was secured 24 cm above the eyes of subject lying supine in a light-shielded laboratory...
October 5, 2016: Journal of Physiological Anthropology
https://www.readbyqxmd.com/read/27699209/loss-of-ikbkap-causes-slow-progressive-retinal-degeneration-in-a-mouse-model-of-familial-dysautonomia
#12
Yumi Ueki, Grisela Ramirez, Ernesto Salcedo, Maureen E Stabio, Frances Lefcort
Familial dysautonomia (FD) is an autosomal recessive congenital neuropathy that is caused by a mutation in the gene for inhibitor of kappa B kinase complex-associated protein (IKBKAP). Although FD patients suffer from multiple neuropathies, a major debilitation that affects their quality of life is progressive blindness. To determine the requirement for Ikbkap in the developing and adult retina, we generated Ikbkap conditional knockout (CKO) mice using a TUBA1a promoter-Cre (Tα1-Cre). In the retina, Tα1-Cre expression is detected predominantly in retinal ganglion cells (RGCs)...
September 2016: ENeuro
https://www.readbyqxmd.com/read/27699185/dataset-of-red-light-induced-pupil-constriction-superimposed-on-post-illumination-pupil-response
#13
Shaobo Lei, Herbert C Goltz, Jaime C Sklar, Agnes M F Wong
We collected and analyzed pupil diameter data from of 7 visually normal participants to compare the maximum pupil constriction (MPC) induced by "Red Only" vs. "Blue+Red" visual stimulation conditions. The "Red Only" condition consisted of red light (640±10 nm) stimuli of variable intensity and duration presented to dark-adapted eyes with pupils at resting state. This condition stimulates the cone-driven activity of the intrinsically photosensitive retinal ganglion cells (ipRGC). The "Blue+Red" condition consisted of the same red light stimulus presented during ongoing blue (470±17 nm) light-induced post-illumination pupil response (PIPR), representing the cone-driven ipRGC activity superimposed on the melanopsin-driven intrinsic activity of the ipRGCs ("The Absence of Attenuating Effect of Red light Exposure on Pre-existing Melanopsin-Driven Post-illumination Pupil Response" Lei et al...
September 2016: Data in Brief
https://www.readbyqxmd.com/read/27696015/a-neurodegenerative-perspective-on-mitochondrial-optic-neuropathies
#14
REVIEW
Patrick Yu-Wai-Man, Marcela Votruba, Florence Burté, Chiara La Morgia, Piero Barboni, Valerio Carelli
Mitochondrial optic neuropathies constitute an important cause of chronic visual morbidity and registrable blindness in both the paediatric and adult population. It is a genetically heterogeneous group of disorders caused by both mitochondrial DNA (mtDNA) mutations and a growing list of nuclear genetic defects that invariably affect a critical component of the mitochondrial machinery. The two classical paradigms are Leber hereditary optic neuropathy (LHON), which is a primary mtDNA disorder, and autosomal dominant optic atrophy (DOA) secondary to pathogenic mutations within the nuclear gene OPA1 that encodes for a mitochondrial inner membrane protein...
December 2016: Acta Neuropathologica
https://www.readbyqxmd.com/read/27693814/retinal-gap-junctions-are-involved-in-rhythmogenesis-of-neuronal-activity-at-remote-locations-study-on-infra-slow-oscillations-in-the-rat-olivary-pretectal-nucleus
#15
Patrycja Orlowska-Feuer, Jagoda S Jeczmien-Lazur, Hanna J Szkudlarek, Marian H Lewandowski
A subpopulation of olivary pretectal nucleus (OPN) neurons fire action potentials in a rhythmic manner with an eruption of activity occurring approximately every two minutes. These infra-slow oscillations depend critically on functional retinal input and are subject to modulation by light. Interestingly, the activity of photoreceptors is necessary for the emergence of the rhythm and while classic photoreceptors (rods and cones) are necessary in darkness and dim light, melanopsin photoreceptors are indispensable in bright light...
December 17, 2016: Neuroscience
https://www.readbyqxmd.com/read/27690288/the-distribution-of-melanopsin-opn4-protein-in-the-human-brain
#16
Juuso S Nissilä, Satu K Mänttäri, Terttu T Särkioja, Hannu J Tuominen, Timo E Takala, Vesa J Kiviniemi, Raija T Sormunen, Seppo Y O Saarela, Markku J Timonen
Until now, melanopsin (OPN4) - a specialized photopigment being responsive especially to blue light wavelengths - has not been found in the human brain at protein level outside the retina. More specifically, OPN4 has only been found in about 2% of retinal ganglion cells (i.e. in intrinsically photosensitive retinal ganglion cells), and in a subtype of retinal cone-cells. Given that Allen Institute for Brain Science has described a wide distribution of OPN4 mRNA in two human brains, we aimed to investigate whether OPN4 is present in the human brain also at protein level...
September 30, 2016: Chronobiology International
https://www.readbyqxmd.com/read/27690169/luminance-and-chromatic-signals-interact-differently-with-melanopsin-activation-to-control-the-pupil-light-response
#17
Pablo A Barrionuevo, Dingcai Cao
Intrinsically photosensitive retinal ganglion cells (ipRGCs) express the photopigment melanopsin. These cells receive afferent inputs from rods and cones, which provide inputs to the postreceptoral visual pathways. It is unknown, however, how melanopsin activation is integrated with postreceptoral signals to control the pupillary light reflex. This study reports human flicker pupillary responses measured using stimuli generated with a five-primary photostimulator that selectively modulated melanopsin, rod, S-, M-, and L-cone excitations in isolation, or in combination to produce postreceptoral signals...
September 1, 2016: Journal of Vision
https://www.readbyqxmd.com/read/27688202/cerebral-neural-correlates-of-differential-melanopic-photic-stimulation-in-humans
#18
Shao-Min Hung, Dan Milea, Annadata Venkata Rukmini, Raymond P Najjar, Joo Huang Tan, Françoise Viénot, Marie Dubail, Sharon Lee Choon Tow, Tin Aung, Joshua J Gooley, Po-Jang Hsieh
Photic stimulation of rods, cones and intrinsically photosensitive melanopsin-containing retinal ganglion cells (ipRGCs) mediates non-visual light responses, including entrainment of circadian rhythms and pupillary light reflex. Unlike visual responses to photic stimulation, the cerebral correlates of non-visual light responses in humans remains elusive. In this study, we used functional magnetic resonance imaging (fMRI) in 14 healthy young participants, to localize cerebral regions which are differentially activated by metameric light that gave rise to different levels of melanopic excitation...
September 26, 2016: NeuroImage
https://www.readbyqxmd.com/read/27669145/a-visual-circuit-uses-complementary-mechanisms-to-support-transient-and-sustained-pupil-constriction
#19
William Thomas Keenan, Alan C Rupp, Rachel A Ross, Preethi Somasundaram, Suja Hiriyanna, Zhijian Wu, Tudor C Badea, Phyllis R Robinson, Bradford B Lowell, Samer S Hattar
Rapid and stable control of pupil size in response to light is critical for vision, but the neural coding mechanisms remain unclear. Here, we investigated the neural basis of pupil control by monitoring pupil size across time while manipulating each photoreceptor input or neurotransmitter output of intrinsically photosensitive retinal ganglion cells (ipRGCs), a critical relay in the control of pupil size. We show that transient and sustained pupil responses are mediated by distinct photoreceptors and neurotransmitters...
September 26, 2016: ELife
https://www.readbyqxmd.com/read/27651995/rhodopsin-7-the-unusual-rhodopsin-in-drosophila
#20
Pingkalai R Senthilan, Charlotte Helfrich-Förster
Rhodopsins are the major photopigments in the fruit fly Drosophila melanogaster. Drosophila express six well-characterized Rhodopsins (Rh1-Rh6) with distinct absorption maxima and expression pattern. In 2000, when the Drosophila genome was published, a novel Rhodopsin gene was discovered: Rhodopsin 7 (Rh7). Rh7 is highly conserved among the Drosophila genus and is also found in other arthropods. Phylogenetic trees based on protein sequences suggest that the seven Drosophila Rhodopsins cluster in three different groups...
2016: PeerJ
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