Visual Pigment

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visual pigment

[′vizh·ə·wəl ′pig·mənt]
Any of various photosensitive pigments of vertebrate and invertebrate photoreceptors.

Visual Pigment


a structural and functional unit of the photosensitive membrane of the photoreceptors of the retina, the rods and cones. The first stage of visual perception—the absorption of quanta of visible light—takes place in the visual pigment. A molecule of visual pigment (molecular mass, approximately 40,000) consists of a chromophore that absorbs light and opsin, a complex of protein and phospholipids. The chromophore of all visual pigments is an aldehyde of vitamin A, or A,—retinal or 3-dehydroretinal. The two forms of opsin (rod and cone) and the two forms of retinal unite in pairs and form four types of visual pigment that differ from one another in their absorption spectra: rhodopsin, or visual purple (the most common rod visual pigment; maximum absorption 500 nanometers [nm]), iodopsin (562 nm), porphyropsin (522 nm), and cyanopsin (620 nm). The primary photochemical link in the mechanism of vision consists in the photoisomerization of retinal, which, under the action of light, changes its curved configuration to a flat one. A chain of dark processes follows this reaction; they lead to the emergence of a visual receptor signal, which is then synaptically transmitted to the sequent nerve elements of the retina—the bipolar and horizontal cells.


Fiziologiia sensornykh sistem, part 1. Leningrad, 1971. Pages 88-125. (Rukovodstvo po fiziologii.)
Wald, G. “The Molecular Basis of Visual Excitation. ”Nature, 1968, vol. 219.


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Visual pigments and colour vision in a nocturnal bird, Strix aluco (Tawny Owl).
together with colleagues at the University of Frankfurt and universities in Vienna, have now been able to show that in mature cones of mice and rats the production of visual pigment is regulated by thyroid hormone.
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Szuts was looking for a visual pigment known as rhodopsin, which is the light-sensing molecule in all known types of eyes.
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Nathans and his colleagues first used a gene that had already been identified as that of the bovine visual pigment called rhodopsin.
I will study opsins, the visual pigments that mediate vision, to shed light into the evolutionary relationship between male colour and female preferences.
TEHRAN (FNA)- Many genetic mutations in visual pigments, spread over millions of years, were required for humans to evolve from a primitive mammal with a dim, shadowy view of the world into a greater ape able to see all the colors in a rainbow.