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Melanopsin

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https://www.readbyqxmd.com/read/29102785/melanopsin-expressing-retinal-ganglion-cells-are-relatively-resistant-to-excitotoxicity-induced-by-n-methyl-d-aspartate
#1
Songtao Wang, Dandan Gu, Peng Zhang, Jing Chen, Yan Li, Honglei Xiao, Guomin Zhou
Excitotoxicity plays an important role in neuronal loss in glaucoma. Previous studies indicate melanopsin-expressing intrinsically photosensitive retinal ganglion cells (ipRGCs) are more injury-resistant. However, whether melanopsin-expressing ipRGCs are resistant to N-methyl-d-aspartate (NMDA) induced excitotoxicity is not well understood. In the present study, we investigated the effects of NMDA-induced excitotoxicity in conventional retinal ganglion cells (RGCs) and melanopsin-expressing ipRGCs in adult mice...
November 2, 2017: Neuroscience Letters
https://www.readbyqxmd.com/read/29070825/melanopsin-a-canonical-light-receptor-mediates-thermal-activation-of-clock-genes
#2
Maria Nathália Moraes, Leonardo Vinícius Monteiro de Assis, Keila Karoline Magalhães-Marques, Maristela Oliveira Poletini, Leonardo Henrique Ribeiro Graciani de Lima, Ana Maria de Lauro Castrucci
Melanopsin (OPN4) is a photo-pigment found in a small subset of intrinsically photosensitive ganglion cells (ipRGCs) of the mammalian retina. These cells play a role in synchronizing the central circadian pacemaker to the astronomical day by conveying information about ambient light to the hypothalamic suprachiasmatic nucleus, the site of the master clock. We evaluated the effect of a heat stimulus (39.5 °C) on clock gene (Per1 and Bmal1) expression in cultured murine Melan-a melanocytes synchronized by medium changes, and in B16-F10 melanoma cells, in the presence of the selective OPN4 antagonist AA92593, or after OPN4 knockdown by small interfering RNA (siRNA)...
October 25, 2017: Scientific Reports
https://www.readbyqxmd.com/read/29053761/the-transcription-factor-prdm16-marks-a-single-retinal-ganglion-cell-subtype-in-the-mouse-retina
#3
Sergio Groman-Lupa, Joseph Adewumi, Ko Uoon Park, Joseph A Brzezinski Iv
Purpose: Retinal ganglion cells (RGC) can be categorized into roughly 30 distinct subtypes. How these subtypes develop is poorly understood, in part because few unique subtype markers have been characterized. We tested whether the Prdm16 transcription factor is expressed by RGCs as a class or within particular ganglion cell subtypes. Methods: Embryonic and mature retinal sections and flatmount preparations were examined by immunohistochemistry for Prdm16 and several other cell type-specific markers...
October 1, 2017: Investigative Ophthalmology & Visual Science
https://www.readbyqxmd.com/read/28973921/long-term-restoration-of-visual-function-in-end-stage-retinal-degeneration-using-subretinal-human-melanopsin-gene-therapy
#4
Samantha R De Silva, Alun R Barnard, Steven Hughes, Shu K E Tam, Chris Martin, Mandeep S Singh, Alona O Barnea-Cramer, Michelle E McClements, Matthew J During, Stuart N Peirson, Mark W Hankins, Robert E MacLaren
Optogenetic strategies to restore vision in patients who are blind from end-stage retinal degenerations aim to render remaining retinal cells light sensitive once photoreceptors are lost. Here, we assessed long-term functional outcomes following subretinal delivery of the human melanopsin gene (OPN4) in the rd1 mouse model of retinal degeneration using an adeno-associated viral vector. Ectopic expression of OPN4 using a ubiquitous promoter resulted in cellular depolarization and ganglion cell action potential firing...
October 17, 2017: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/28973746/analysis-of-melanopsin-gene-expression-in-the-rabbit-retina-at-different-ages
#5
M M Lira-Carrera, B E Gutiérrez-Amavizca, L J Álvarez-Araujo, M Aguirre-Ramírez, J A Pérez-León
Melanopsin is the photopigment of intrinsically photosensitive retinal ganglion cells that mediate non-visual responses to light. The aim of this study was to describe and analyze melanopsin gene expression in the rabbit retina at different ages and compare its expression with the prototypic gene of retinal ganglion cells (Thy-1 gene). Expression levels of OPN4, Thy-1, and GADPH genes were measured by real-time PCR at 3, 4, 8, 11, 12, 17, 19, 20, 23, 27, 32, and 47 postnatal days. We also regrouped the days before and after day 12 of life (pre-photic and post-photic stage, respectively)...
September 27, 2017: Genetics and Molecular Research: GMR
https://www.readbyqxmd.com/read/28959188/nmda-receptors-contribute-to-retrograde-synaptic-transmission-from-ganglion-cell-photoreceptors-to-dopaminergic-amacrine-cells
#6
Lei-Lei Liu, Nathan J Spix, Dao-Qi Zhang
Recently, a line of evidence has demonstrated that the vertebrate retina possesses a novel retrograde signaling pathway. In this pathway, phototransduction is initiated by the photopigment melanopsin, which is expressed in a small population of retinal ganglion cells. These ganglion cell photoreceptors then signal to dopaminergic amacrine cells (DACs) through glutamatergic synapses, influencing visual light adaptation. We have previously demonstrated that in Mg(2+)-containing solution, α-amino-3-hydroxyl-5-methyl-4-isoxazole-propionate (AMPA) receptors mediate this glutamatergic transmission...
2017: Frontiers in Cellular Neuroscience
https://www.readbyqxmd.com/read/28955293/melanopsin-mediated-acute-light-responses-measured-in-winter-and-in-summer-seasonal-variations-in-adults-with-and-without-cataracts
#7
Mirjam Münch, Myriam Ladaique, Ségolène Roemer, Kattayoon Hashemi, Aki Kawasaki
Seasonal adaptation is a ubiquitous behavior seen in many species on both global hemispheres and is conveyed by changing photoperiods. In humans this seasonal adaptation is less apparent, in part because changes in daylength are masked by the use of electrical lighting at night. On the other hand, cataracts which reduce light transmission, may compound seasonal changes related to the reduced daylength of winter. To better understand the effects of different photoperiod lengths in healthy adults without and with cataracts, we tested their melanopsin-mediated light responses in summer vs...
2017: Frontiers in Neurology
https://www.readbyqxmd.com/read/28910447/orexin-a-suppresses-signal-transmission-to-dopaminergic-amacrine-cells-from-outer-and-inner-retinal-photoreceptors
#8
Sheng-Nan Qiao, Wei Zhou, Lei-Lei Liu, Dao-Qi Zhang, Yong-Mei Zhong
Purpose: The neuropeptides orexin-A and orexin-B are widely expressed in the vertebrate retina; however, their role in visual function is unclear. This study investigates whether and how orexins modulate signal transmission to dopaminergic amacrine cells (DACs) from both outer retinal photoreceptors (rods and cones) and inner retinal photoreceptors (melanopsin-expressing intrinsically photosensitive retinal ganglion cells [ipRGCs]). Methods: A whole-cell voltage-clamp technique was used to record light-induced responses from genetically labeled DACs in flat-mount mouse retinas...
September 1, 2017: Investigative Ophthalmology & Visual Science
https://www.readbyqxmd.com/read/28882814/opsin-3-and-4-mediate-light-induced-pulmonary-vasorelaxation-that-is-potentiated-by-g-protein-receptor-kinase-2-inhibition
#9
Sebastian Barreto Ortiz, Daijiro Hori, Yohei Nomura, Xin Yun, Haiyang Jiang, Hwanmee Yong, James Chen, Sam Paek, Deepesh Pandey, Gautam Sikka, Anil Bhatta, Andrew Gillard, Jochen Steppan, Jae Hyung Kim, Hideo Adachi, Viachaslau Barodka, Lewis Romer, Steven S An, Larissa A Shimoda, Lakshmi Santhanam, Dan E Berkowitz
We recently demonstrated that blue light induces vasorelaxation in the systemic mouse circulation, a phenomenon mediated by the non-visual G protein-coupled receptor (GPCR) melanopsin (opsin 4; Opn4). Here we tested the hypothesis that non-visual opsins mediate photorelaxation in the pulmonary circulation. We discovered Opsin 3 (Opn3), Opn4, and G-protein coupled receptor kinase 2 (GRK2) in rat pulmonary arteries (PAs) and in pulmonary arterial smooth muscle cells (PASMCs), where the opsins interact directly with GRK2 as demonstrated with a proximity ligation assay...
September 7, 2017: American Journal of Physiology. Lung Cellular and Molecular Physiology
https://www.readbyqxmd.com/read/28880021/long-term-expression-of-melanopsin-and-channelrhodopsin-causes-no-gross-alterations-in-the-dystrophic-dog-retina
#10
B Ameline, K-T Tshilenge, M Weber, M Biget, L Libeau, R Caplette, A Mendes-Madeira, N Provost, C Guihal, S Picaud, P Moullier, V Pichard, T Cronin, C Isiegas
Several preclinical studies have investigated the potential of algal channelrhodopsin and human melanopsin as optogenetic tools for vision restoration. In the present study, we assessed the potentially deleterious effects of long-term expression of these optogenes on the diseased retina in a large animal model of retinal degeneration, the RPE65-deficient Briard dog model of Leber congenital amaurosis. Intravitreal injection of adeno-associated virus vectors expressing channelrhodopsin and melanopsin had no effect on retinal thickness over a 16-month period post injection...
September 7, 2017: Gene Therapy
https://www.readbyqxmd.com/read/28874778/the-impact-of-temporal-modulations-in-irradiance-under-light-adapted-conditions-on-the-mouse-suprachiasmatic-nuclei-scn
#11
Rachel Dobb, Franck Martial, Daniel Elijah, Riccardo Storchi, Timothy M Brown, Robert J Lucas
Electrophysiological responses of SCN neurons to light steps are well established, but responses to more natural modulations in irradiance have been much less studied. We address this deficit first by showing that variations in irradiance for human subjects are biased towards low temporal frequencies and small magnitudes. Using extracellular recordings we show that neurons in the mouse SCN are responsive to stimuli with these characteristics, tracking sinusoidal modulations in irradiance best at lower temporal frequencies and responding to abrupt changes in irradiance over a range of commonly encountered contrasts...
September 5, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28871236/non-visual-photopigments-effects-of-constant-light-emitting-diode-light-exposure-on-the-inner-retina-of-wistar-rats
#12
María M Benedetto, Mario E Guido, María A Contin
The retina is part of the central nervous system specially adapted to capture light photons and transmit this information to the brain through photosensitive retinal cells involved in visual and non-visual activities. However, excessive light exposure may accelerate genetic retinal diseases or induce photoreceptor cell (PRC) death, finally leading to retinal degeneration (RD). Light pollution (LP) caused by the characteristic use of artificial light in modern day life may accelerate degenerative diseases or promote RD and circadian desynchrony...
2017: Frontiers in Neurology
https://www.readbyqxmd.com/read/28801634/mapping-physiological-inputs-from-multiple-photoreceptor-systems-to-dopaminergic-amacrine-cells-in-the-mouse-retina
#13
Xiwu Zhao, Kwoon Y Wong, Dao-Qi Zhang
In the vertebrate retina, dopamine is synthesized and released by a specialized type of amacrine cell, the dopaminergic amacrine cell (DAC). DAC activity is stimulated by rods, cones, and melanopsin-expressing intrinsically photosensitive retinal ganglion cells upon illumination. However, the relative contributions of these three photoreceptor systems to the DAC light-induced response are unknown. Here we found that rods excite dark-adapted DACs across a wide range of stimulation intensities, primarily through connexin-36-dependent rod pathways...
August 11, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28782536/immunolesion-of-melanopsin-neurons-causes-gonadal-regression-in-pekin-drakes-anas-platyrhynchos-domesticus
#14
H Potter, E Alenciks, K Frazier, A Porter, G S Fraley
Several light sensitive receptors have been described in the avian brain that are thought to regulate the reproductive axis independently from the eyes and pineal gland.Recently, our lab has described the presence of three of these photoneuroendocrine systems in the Pekin duck: opsin, opsin 5, & melanopsin. We set out to test the hypothesis that melanopsin receptive neurons are necessary to maintain seasonal reproductive status along with growth and development in the Pekin drake. To accomplish these goals we first investigated 50-week-old Pekin drakes that were housed in the aviary at Hope College under long day length (18 hrs lights on) conditions in floor pens...
August 4, 2017: General and Comparative Endocrinology
https://www.readbyqxmd.com/read/28758193/melanopsin-ganglion-cell-outer-retinal-dendrites-morphologically-distinct-and-asymmetrically-distributed-in-the-mouse-retina
#15
Katelyn B Sondereker, Jessica R Onyak, Shakib W Islam, Christopher L Ross, Jordan M Renna
A small population of retinal ganglion cells expresses the photopigment melanopsin and function as autonomous photoreceptors. They encode global luminance levels critical for light-mediated non-image forming visual processes including circadian rhythms and the pupillary light reflex. There are five melanopsin ganglion cell subtypes (M1-M5). M1 and displaced M1 (M1d) cells have dendrites that ramify within the outermost layer of the inner plexiform layer. It was recently discovered that some melanopsin ganglion cells extend dendrites into the outer retina...
July 31, 2017: Journal of Comparative Neurology
https://www.readbyqxmd.com/read/28751938/led-lights-with-hidden-intensity-modulated-blue-channels-aiming-for-enhanced-subconscious-visual-responses
#16
Garen Vartanian, Kwoon Y Wong, Pei-Cheng Ku
A new form of light-emitting diode (LED) light suitable for general illumination is proposed to enhance subconscious, nonimage-forming visual responses, which are essential to our well-being. Pulsing light has been shown to reduce photoreceptor adaptation and elicit stronger subconscious visual responses at an indoor illumination level. Using the silent substitution technique, a melanopsin-selective flicker can be added into white light. A linear optimization algorithm was developed to suppress any perceivable fluctuation of light intensity and colors of illuminated objects...
June 2017: IEEE Photonics Journal
https://www.readbyqxmd.com/read/28716667/pupillometric-evaluation-of-the-melanopsin-containing-retinal-ganglion-cells-in-mitochondrial-and-non-mitochondrial-optic-neuropathies
#17
Shakoor Ba-Ali, Henrik Lund-Andersen
In recent years, chromatic pupillometry is used in humans to evaluate the activity of melanopsin expressing intrinsic photosensitive retinal ganglion cells (ipRGCs). Blue light is used to stimulate the ipRGCs and red light activates the rod/cone photoreceptors. The late re-dilation phase of pupillary light reflex is primarily driven by the ipRGCs. Optic neuropathies i.e. Leber hereditary optic neuropathy (LHON), autosomal dominant optic atrophy (ADOA), nonarteritic anterior ischemic optic neuropathy (NAION), glaucoma, optic neuritis and idiopathic intracranial hypertension (IIH) are among the diseases, which have been subject to pupillometric studies...
July 14, 2017: Mitochondrion
https://www.readbyqxmd.com/read/28708670/color-pupillography-in-dorsal-midbrain-syndrome
#18
Carina B Kelbsch, Fumiatsu Maeda, Torsten Strasser, Tobias M Peters, Barbara J C Wilhelm, Helmut M Wilhelm
OBJECTIVE: The purpose of this study was to evaluate the pupil response to chromatic stimuli in patients with lesions in the dorsal midbrain and possibly gain new insights into the afferent pupillary pathways. METHODS: Color pupillography was performed in 5 patients with dorsal midbrain syndrome (DMS), and their results were compared with those of 20 healthy control subjects. We used full-field red stimuli (605 nm) that primarily address the rod/cone system and blue stimuli (420 nm) that preferentially activate intrinsically photosensitive retinal ganglion cells (ipRGCs) directly, with a duration of 4 seconds and a stimulus intensity of 28 lx corneal illumination under mesopic conditions...
September 2017: Journal of Neuro-ophthalmology: the Official Journal of the North American Neuro-Ophthalmology Society
https://www.readbyqxmd.com/read/28697776/exposure-to-blue-light-during-lunch-break-effects-on-autonomic-arousal-and-behavioral-alertness
#19
Emi Yuda, Hiroki Ogasawara, Yutaka Yoshida, Junichiro Hayano
BACKGROUND: Exposures to melanopsin-stimulating (melanopic) component-rich blue light enhance arousal level. We examined their effects in office workers. Eight healthy university office workers were exposed to blue and orange lights for 30 min during lunch break on different days. We compared the effects of light color on autonomic arousal level assessed by heart rate variability (HRV) and behavioral alertness by psychomotor vigilance tests (PVT). Heart rate was higher and high-frequency (HF, 0...
July 11, 2017: Journal of Physiological Anthropology
https://www.readbyqxmd.com/read/28697361/vision-melanopsin-as-a-raumgeber
#20
Manuel Spitschan, Geoffrey K Aguirre
Two new studies show that neural systems receiving inputs from the melanopsin-containing retinal ganglion cells encode spatial information and therefore see the world in more detail than previously thought.
July 10, 2017: Current Biology: CB
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