Melanopsin, Ganglion-Cell Photoreceptors, and Mammalian Photoentrainment

  title={Melanopsin, Ganglion-Cell Photoreceptors, and Mammalian Photoentrainment},
  author={Mark D. Rollag and David M. Berson and Ignacio Provencio},
  journal={Journal of Biological Rhythms},
  pages={227 - 234}
An understanding of the retinal mechanisms in mammalian photoentrainment will greatly facilitate optimization of the wavelength, intensity, and duration of phototherapeutic treatments designed to phase shift endogenous biological rhythms. A small population of widely dispersed retinal ganglion cells projecting to the suprachiasmatic nucleus in the hypothalamus is the source of the critical photic input. Recent evidence has shown that many of these ganglion cells are directly photosensitive and… 

Figures from this paper

Phototransduction in ganglion-cell photoreceptors

  • D. Berson
  • Biology
    Pflügers Archiv - European Journal of Physiology
  • 2007
The overwhelming evidence that melanopsin serves as the photopigment in these cells is summarized and the emerging evidence that the downstream signaling cascade, including the light-gated channel, might resemble those found in rhabdomeric invertebrate photoreceptors is reviewed.

Melanopsin phototransduction: beyond canonical cascades

Recent findings and discoveries are discussed that have challenged the prevailing view of melanopsin phototransduction as a single pathway that influences solely non-image forming functions.

Immunohistochemical evidence of a melanopsin cone in human retina.

The presence of melanopsin in human cones suggests image and non-image-forming roles in visual responses at both the cone input and ganglion cell output stages and their involvement in a broad spectrum of irradiance detection functions in the visual system.

[Phototransduction mediated by melanopsin in intrinsically photosensitive retinal ganglion cells].

Melanopsin is the most recent photopigment described. As all the other opsins, it attaches in the retina as chromophore. Its amino acid sequence resembles more invertebrate opsins than those of

The Evolution and Function of Melanopsin in Craniates

The evolutionary history of the melanopsin gene, its diverse patterns of expression and transcriptional output, the functional roles so far determined, and the clinical significance of this critical and phylogenetically most ancient opsin-based system of irradiance detection are discussed.

Melanopsin and the Non‐visual Photochemistry in the Inner Retina of Vertebrates

Light is shed on the visual cycle taking place in the inner retina of mammals and nonmammalian vertebrates and the state of the art in the nonvisual photochemistry of vertebrates is discussed.

Adaptation to steady light by intrinsically photosensitive retinal ganglion cells

  • M. H. DoK. Yau
  • Biology
    Proceedings of the National Academy of Sciences
  • 2013
Interestingly, in incremental-flash-on-background experiments, the ipRGC’s receptor current showed a flash sensitivity that adapted in background light according to the Weber–Fechner relation, well known to describe the adaptation behavior of rods and cones.

Diverse Cell Types, Circuits, and Mechanisms for Color Vision in the Vertebrate Retina.

The retina has evolved elaborate color opponent circuitry for extracting wavelength information by comparing the activities of different photoreceptor types broadly tuned to different parts of the visible spectrum, and circuits that may mediate these interactions are considered.

Functional diversity of melanopsins and their global expression in the teleost retina

Electrophysiological and spectrophotometric studies demonstrate that all five zebrafish melanopsins encode a functional photopigment with peak spectral sensitivities that range from 470 to 484 nm, and reveal the presence of both invertebrate-like and vertebrates-like forms of melanopsin in the teleost retina, and indicate that photopIGment bistability is not a universal property of the melanopsIN family.

Immunocytochemical Localization of Melanopsin-immunoreactive Neurons in the Mouse Visual Cortex

The data indicate that melanopsin is located in specific neurons and surprisingly widespread in visual cortex, which raises the need of the functional study of melanopigment in central visual areas outside the retina.



Melanopsin-Containing Retinal Ganglion Cells: Architecture, Projections, and Intrinsic Photosensitivity

It is shown that melanopsin is present in cell bodies, dendrites, and proximal axonal segments of a subset of rat RGCs, most likely the visual pigment of phototransducing R GCs that set the circadian clock and initiate other non–image-forming visual functions.

Diminished Pupillary Light Reflex at High Irradiances in Melanopsin-Knockout Mice

It is reported that in mice with the melanopsin gene ablated, RGCs retrograde-labeled from the suprachiasmatic nuclei were no longer intrinsically photosensitive, although their number, morphology, and projections were unchanged.

Melanopsin: An opsin in melanophores, brain, and eye.

Melanopsin mRNA is expressed in hypothalamic sites thought to contain deep brain photoreceptors and in the iris, a structure known to be directly photosensitive in amphibians, and expression in retinal and nonretinal tissues suggests a role in vision and nonvisual photoreceptive tasks.

Melanopsin retinal ganglion cells receive bipolar and amacrine cell synapses

Observations suggested that rod and/or cone signals may be capable of modifying the intrinsic light response in melanopsin‐expressing retinal ganglion cells.

Melanopsin in cells of origin of the retinohypothalamic tract

It is shown that most retinal ganglion cells that project to the SCN express the photopigment melanopsin, which mediates circadian entrainment in mice.

Phototransduction by Retinal Ganglion Cells That Set the Circadian Clock

It is shown that retinal ganglion cells innervating the SCN are intrinsically photosensitive, and depolarized in response to light even when all synaptic input from rods and cones was blocked.

The circadian photopigment melanopsin is expressed in the blind subterranean mole rat, Spalax

It is shown, using in situ hybridization and immunohistochemistry, that melanopsin, a recently identified opsin, is expressed in retinal ganglion cells which also co-store PACAP, a neurotransmitter of the RHT.

The Photopigment Melanopsin Is Exclusively Present in Pituitary Adenylate Cyclase-Activating Polypeptide-Containing Retinal Ganglion Cells of the Retinohypothalamic Tract

Cloned rat melanopsin photopigment cDNA is cloned and in situ hybridization histochemistry combined with immunohistochemistry and colocalization studies reveal that melanops in was found exclusively in the PACAP-containing retinal ganglion cells located at the surface of somata and dendrites.

Zebrafish melanopsin: isolation, tissue localisation and phylogenetic position.

Opsins and mammalian photoentrainment

Only when melanopsin and other candidates for OP479 have been functionally expressed, and shown to encode a photopigment that matches the action spectrum of OP479, can firm conclusions about the identity of the non-rod, non-cone ocular photoreceptor of mammals be made.