Related Experiment Video
Updated: Aug 8, 2026
08:38
Transretinal ERG Recordings from Mouse Retina: Rod and Cone Photoresponses
Published on: March 14, 2012
Molecular mechanisms characterizing cone photoresponses
Shuji Tachibanaki1, Yoshie Shimauchi-Matsukawa, Daisuke Arinobu
1Graduate School of Frontier Biosciences, Osaka University, Suita, Japan. banaki@fbs.osaka-u.ac.jp
Photochemistry and Photobiology
|May 19, 2006
Summary
Cone cells have lower light sensitivity and faster responses than rod cells due to less signal amplification and rapid visual pigment phosphorylation. This study outlines the molecular mechanisms behind these differences in vertebrate vision.
Area of Science:
- Vision science
- Molecular biology
- Retinal physiology
Background:
- Vertebrate retina contains rods for twilight vision and cones for daylight vision.
- Rods and cones exhibit distinct photoresponse characteristics, including light sensitivity and response speed.
- The molecular mechanisms underlying cone photoresponses remain largely unknown due to isolation difficulties.
Purpose of the Study:
- To elucidate the molecular mechanisms differentiating cone and rod phototransduction.
- To explain the lower light-sensitivity and faster photoresponse kinetics of cones.
Main Methods:
- Developed a novel method for purifying cones from carp retina using density gradient centrifugation.
- Analyzed molecular differences in phototransduction pathways between isolated rods and cones.
Main Results:
- Identified less effective signal amplification in cones, correlating with their lower light sensitivity.
- Demonstrated significantly more rapid visual pigment phosphorylation in cones compared to rods.
- Attributed rapid cone phosphorylation to exceptionally high total kinase activity, enabling quick recovery.
Conclusions:
- The study outlines the molecular basis for distinct rod and cone photoresponse characteristics.
- Lower signal amplification explains cone light sensitivity, while rapid phosphorylation accounts for their faster recovery kinetics.
Related Concept Videos
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...
01:32The 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.
02:00Photoreceptors and Plant Responses to Light
Light plays a significant role in regulating the growth and development of plants. In addition to providing energy for photosynthesis, light provides other important cues to regulate a range of developmental and physiological responses in plants.
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,...
01:29The Photochemical Reaction Center
Reaction centers are pigment-protein complexes that initiate energy conversion from photons to chemical entities. Therefore, photochemical reaction center is a more appropriate term that describes these complexes. The Nobel laureates Robert Emerson and William Arnold provided the first experimental evidence of photochemical reaction centers by demonstrating the participation of nearly 2,500 chlorophyll molecules for the release of just one molecule of oxygen. Despite thousands of photosynthetic...
01:15The Antenna Complex
Plants and other photosynthetic organisms comprise pigments capable of absorption of direct sunlight. These pigments are present in the reaction center - the main site of photochemical reactions as well as in the antenna complex. Under average light conditions, the rate at which reaction center pigments absorb light is far below the electron transport chain's capacity. As a result, the reaction center alone cannot provide enough energy to drive photosynthesis. The photosynthetic efficiency can...