Can We See with Melanopsin?

Annual Review of Vision Science, Год журнала: 2020, Номер 6(1), С. 453 - 468

Опубликована: Июнь 3, 2020

A small fraction of mammalian retinal ganglion cells are directly photoreceptive thanks to their expression the photopigment melanopsin. These intrinsically photosensitive (ipRGCs) have well-established roles in a variety reflex responses changes ambient light intensity, including circadian photoentrainment. In this article, we review growing evidence, obtained primarily from laboratory mice and humans, that ability sense via melanopsin is also an important component perceptual form vision. Melanopsin photoreception has low temporal resolution, making it fundamentally biased toward detecting coarse patterns rather than fine details. Nevertheless, can indirectly impact high-acuity vision by driving aspects adaptation ranging pupil constriction visual circuit performance. contributes perceptions brightness, recent data suggest influences appearance not only overall scene but low-frequency patterns.

Язык: Английский

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Overlapping morphological and functional properties between M4 and M5 intrinsically photosensitive retinal ganglion cells

The Journal of Comparative Neurology, Год журнала: 2019, Номер 528(6), С. 1028 - 1040

Опубликована: Ноя. 6, 2019

Abstract Multiple retinal ganglion cell (RGC) types in the mouse retina mediate pattern vision by responding to specific features of visual scene. The M4 and M5 melanopsin‐expressing, intrinsically photosensitive (ipRGC) subtypes are two RGC that thought play major roles vision. ipRGCs overlap population with ON‐alpha RGCs, while were recently reported exhibit opponent responses different wavelengths light (color opponency). Despite their seemingly distinct processing, previous reports have suggested these populations may morphological functional properties, which calls into question whether fact types. Here, we show classes ipRGCs, but they cannot be exclusively differentiated based on color opponency dendritic morphology as previously reported. Instead, find can only distinguished soma size number branch points combination SMI‐32 immunoreactivity. These results important implications for clearly defining behavior.

Язык: Английский

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Projections of ipRGCs and conventional RGCs to retinorecipient brain nuclei

The Journal of Comparative Neurology, Год журнала: 2020, Номер 529(8), С. 1863 - 1875

Опубликована: Окт. 26, 2020

Retinal ganglion cells (RGCs), the output neurons of retina, allow us to perceive our visual environment. RGCs respond rod/cone input through retinal circuitry, however, a small population are in addition intrinsically photosensitive (ipRGCs) and project unique targets brain modulate broad range subconscious behaviors such as pupil constriction circadian photoentrainment. Despite discovery ipRGCs nearly two decades ago, there is still little information about how or if conventional (non-ipRGCs) target ipRGC-recipient nuclei influence behavior. Using dual recombinase fluorescent reporter strategy, we showed that innervate many nuclei, apart from suprachiasmatic nucleus. We revealed previously unrecognized stratification patterns innervation ventral portion lateral geniculate Further, found percent across ipsi- contralateral differ. Our data provide blueprint understand different regions behaviors.

Язык: Английский

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Melanopsin phototransduction: beyond canonical cascades

Journal of Experimental Biology, Год журнала: 2021, Номер 224(23)

Опубликована: Ноя. 29, 2021

Melanopsin is a visual pigment that expressed in small subset of intrinsically photosensitive retinal ganglion cells (ipRGCs). It involved regulating non-image forming behaviors, such as circadian photoentrainment and the pupillary light reflex, while also playing role many aspects image-forming vision, contrast sensitivity. was initially discovered melanophores skin frog Xenopus, subsequently found rat, mouse primate retinas. ipRGCs were thought to be single cell population, melanopsin activate single, invertebrate-like Gq/transient receptor potential canonical (TRPC)-based phototransduction cascade within these cells. However, 20 years since discovery melanopsin, our knowledge this has expanded dramatically. Six ipRGC subtypes have now been identified mouse, each with unique morphological, physiological functional properties. Multiple other species, suggesting type diversity general feature system. This led renewed interest may not follow Gq/TRPC or plethora organisms express photopigment. In Review, we discuss recent findings discoveries challenged prevailing view pathway influences solely functions.

Язык: Английский

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Unusual phototransduction via cross-motif signaling from G _q to adenylyl cyclase in intrinsically photosensitive retinalganglion cells

Proceedings of the National Academy of Sciences, Год журнала: 2022, Номер 120(1)

Опубликована: Дек. 29, 2022

Nonimage-forming vision in mammals is mediated primarily by melanopsin (OPN4)-expressing, intrinsically photosensitive retinal ganglion cells (ipRGCs). In mouse M1-ipRGCs, predominantly activates, via Gαq,11,14, phospholipase C-β4 to open transient receptor 6 (TRPC6) and TRPC7 channels. M2- M4-ipRGCs, however, a prominent phototransduction mechanism involves the opening of hyperpolarization- cyclic nucleotide-gated channels nucleotide, although upstream steps remain uncertain. We report here experiments, on with photo-uncaging nucleotides virally expressed CNGA2 conclude that second messenger adenosine monophosphate (cAMP) - very surprising considering guanosine (cGMP) used almost all nucleotide-mediated mechanisms across animal kingdom. further found G protein likewise Gq, which its Gβγ subunits directly activates adenylyl cyclase (AC). Our findings are demonstration native cell cross-motif GPCR signaling pathway from Gq AC specific function.

Язык: Английский

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