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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
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...
October 4, 2016: General and Comparative Endocrinology
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
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
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
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...
September 30, 2016: Acta Neuropathologica
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...
September 28, 2016: Neuroscience
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
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
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
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
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
Marta Agudo-Barriuso, Francisco M Nadal-Nicolás, María H Madeira, Giuseppe Rovere, Beatriz Vidal-Villegas, Manuel Vidal-Sanz
No abstract text is available yet for this article.
August 2016: Neural Regeneration Research
Maria Angeles Bonmati-Carrion, Konstanze Hild, Cheryl Isherwood, Stephen J Sweeney, Victoria L Revell, Debra J Skene, Maria Angeles Rol, Juan Antonio Madrid
Intrinsically photosensitive retinal ganglion cells (ipRGCs), whose photopigment melanopsin has a peak of sensitivity in the short wavelength range of the spectrum, constitute a common light input pathway to the olivary pretectal nucleus (OPN), the pupillary light reflex (PLR) regulatory centre, and to the suprachiasmatic nuclei (SCN), the major pacemaker of the circadian system. Thus, evaluating PLR under short wavelength light (λmax ≤ 500 nm) and creating an integrated PLR parameter, as a possible tool to indirectly assess the status of the circadian system, becomes of interest...
2016: PloS One
Russell N Van Gelder
Using a targeted chemogenetic approach, a new study provides evidence for a unique pathway for neural processing of light information from melanopsin ganglion cells. These results suggest how light can have both alerting and sleep-promoting effects in mice.
September 12, 2016: Current Biology: CB
Prakash Adhikari, Andrew J Zele, Ravi Thomas, Beatrix Feigl
It is difficult to detect visual function deficits in patients at risk for glaucoma (glaucoma suspects) and at early disease stages with conventional ophthalmic tests such as perimetry. To this end, we introduce a novel quadrant field measure of the melanopsin retinal ganglion cell mediated pupil light response corresponding with typical glaucomatous arcuate visual field defects. The melanopsin-mediated post-illumination pupil response (PIPR) was measured in 46 patients with different stages of glaucoma including glaucoma suspects and compared to a healthy group of 21 participants with no disease...
2016: Scientific Reports
Jessica Bruijel, Wisse P van der Meijden, Denise Bijlenga, Farangis Dorani, Joris E Coppens, Bart H W Te Lindert, J J Sandra Kooij, Eus J W Van Someren
Melanopsin-containing retinal ganglion cells play an important role in the non-image forming effects of light, through their direct projections on brain circuits involved in circadian rhythms, mood and alertness. Individual differences in the functionality of the melanopsin-signaling circuitry can be reliably quantified using the maximum post-illumination pupil response (PIPR) after blue light. Previous protocols for acquiring PIPR relied on the use of mydriatics to dilate the light-exposed eye. However, pharmacological pupil dilation is uncomfortable for the participants and requires ophthalmological expertise...
2016: Biology
Elisabeth Anne Obara, Jens Hannibal, Steffen Heegaard, Jan Fahrenkrug
PURPOSE: Multiple studies have shown overwhelming evidence supporting the impairment of melanopsin function due to glaucoma. However, few studies have been carried out in humans analyzing the histology of melanopsin-expressing retinal ganglion cells (mRGCs) in retinas with glaucoma. The aim of this study was to analyze the pattern of expression of mRGCs relative to RGCs in the normal retina and retinas harboring varying stages of glaucoma. METHODS: Paraffin-embedded human donor eyes with glaucoma (n = 11) and age-matched controls (n = 10) were obtained from Department of Pathology at Rigshospital (Copenhagen, Denmark) for detection of RNA binding protein with multiple splicing (RBPMS) and melanopsin by immunohistochemistry...
September 1, 2016: Investigative Ophthalmology & Visual Science
Takuma Sonoda, Seul Ki Lee
No abstract text is available yet for this article.
August 31, 2016: Journal of Neuroscience: the Official Journal of the Society for Neuroscience
Anna Matynia, Eileen Nguyen, Xiaoping Sun, Frank W Blixt, Sachin Parikh, Jason Kessler, Luis Pérez de Sevilla Müller, Samer Habib, Paul Kim, Zhe Z Wang, Allen Rodriguez, Andrew Charles, Steven Nusinowitz, Lars Edvinsson, Steven Barnes, Nicholas C Brecha, Michael B Gorin
The ability of light to cause pain is paradoxical. The retina detects light but is devoid of nociceptors while the trigeminal sensory ganglia (TG) contain nociceptors but not photoreceptors. Melanopsin-expressing intrinsically photosensitive retinal ganglion cells (ipRGCs) are thought to mediate light-induced pain but recent evidence raises the possibility of an alternative light responsive pathway independent of the retina and optic nerve. Here, we show that melanopsin is expressed in both human and mouse TG neurons...
2016: Frontiers in Neural Circuits
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