Related Experiment Video
Updated: May 26, 2026
13:02
An Isolated Retinal Preparation to Record Light Response from Genetically Labeled Retinal Ganglion Cells
Published on: January 26, 2011
Intrinsically photosensitive retinal ganglion cells
Gary E Pickard1, Patricia J Sollars
1School of Veterinary Medicine and Biomedical Sciences, University of Nebraska, Lincoln, NE 68583, USA. gpickard2@unl.edu
Reviews of Physiology, Biochemistry and Pharmacology
|December 14, 2011
Summary
Intrinsically photosensitive retinal ganglion cells (ipRGCs) are novel photoreceptors in the eye. These cells, expressing melanopsin, regulate circadian rhythms, sleep, and the pupillary light reflex.
Area of Science:
- Ophthalmology
- Neuroscience
- Cell Biology
Background:
- Intrinsically photosensitive retinal ganglion cells (ipRGCs) were predicted by decades of research.
- The discovery of melanopsin in retinal ganglion cells confirmed their photoreceptor role.
Purpose of the Study:
- To review the historical context and discoveries surrounding ipRGCs.
- To summarize current understanding of ipRGC phototransduction and function.
- To outline future research directions for these unique neurons.
Main Methods:
- Review of early observational data and subsequent molecular discoveries.
- Analysis of phototransduction mechanisms in ipRGCs.
- Examination of ipRGC connectivity and subtypes in rodents.
Main Results:
- ipRGCs possess a novel photopigment, melanopsin.
- Their phototransduction resembles invertebrate photoreceptors, mediated by transient receptor potential channels.
- ipRGCs influence circadian rhythms, pupillary reflexes, sleep, and autonomic functions.
Conclusions:
- ipRGCs represent a distinct class of photoreceptors with significant roles beyond vision.
- Further research is needed to fully elucidate their properties and functions.
- Understanding ipRGCs offers insights into neural regulation of physiology and behavior.
Related Concept Videos
01:32The Retina
The retina is a layer of nervous tissue at the back of the eye that transduces light into neural signals. This process, called phototransduction, is carried out by rod and cone photoreceptor cells in the back of the retina.
01:22Photoreceptors and Visual Pathways
At the molecular level, visual signals trigger transformations in photopigment molecules, resulting in changes in the photoreceptor cell's membrane potential. The photon's energy level is denoted by its wavelength, with each specific wavelength of visible light associated with a distinct color. The spectral range of visible light, classified as electromagnetic radiation, spans from 380 to 720 nm. Electromagnetic radiation wavelengths exceeding 720 nm fall under the infrared category, whereas...
01:20Anatomy of the Eyeball
The eye is a spherical, hollow structure composed of three tissue layers. The outer layer — the fibrous tunic, comprises the sclera — a white structure — and the cornea, which is transparent. The sclera encompasses some of the ocular surface, most of which is not visible. However, the 'white of the eye' is distinctively visible in humans compared to other species. The cornea, a clear covering at the front of the eye, enables light penetration. The eye's middle layer, the vascular tunic,...
01:11Channel Rhodopsins
Most organisms use photoreceptors to sense and respond to light. Examples of photoreceptors include bacteriorhodopsins and bacteriophytochromes in some bacteria, phytochromes in plants, and rhodopsins in the photoreceptor cells of the vertebral retina. The light-sensitive property of these receptors is because of the bound chromophores, such as bilin in the phytochromes and retinal in the rhodopsins.
Rhodopsins belong to the family of cell surface proteins called G-protein coupled receptors,...
Rhodopsins belong to the family of cell surface proteins called G-protein coupled receptors,...
01:21G-Protein Gated Ion Channels
GPCRs are primarily responsible for our sense of smell, taste, and vision. The binding of a sensory stimulus activates GPCR to stimulate effector proteins, many of which are ion channels in the sensory organs. GPCRs modulate the opening and closing of the target ion channels either directly by binding them, or by releasing second messengers that activate these channels. As ions move across the membrane, the membrane potential is altered, which induces an appropriate response.
Sensory organs,...
Sensory organs,...
00:50Unrenewable Cells
In humans, the photoreceptor cells of the eye and sensory hair cells of the ear lack stem cells. These cells are thus unrenewable and cannot be replaced when they are damaged or destroyed.
Photoreceptors
The retina is composed of several layers and contains specialized cells called photoreceptors. The photoreceptors (rods and cones) change their membrane potential when stimulated by light energy. There are two types of photoreceptors—rods and cones—which differ in the shape of their outer...
Photoreceptors
The retina is composed of several layers and contains specialized cells called photoreceptors. The photoreceptors (rods and cones) change their membrane potential when stimulated by light energy. There are two types of photoreceptors—rods and cones—which differ in the shape of their outer...