rhodopsin

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rhodopsin

 [ro-dop´sin]
visual purple: a photosensitive purple-red chromoprotein in the retinal rods that is bleached to visual yellow (all-transretinal) by light, thereby stimulating retinal sensory endings. Lack of rhodopsin results in night blindness. Vitamin A is the primary source of rhodopsin.

rho·dop·sin

(rō-dop'sin), [MIM*180380]
A purplish-red thermolabile protein, MW about 40,000, found in the external segments of the rods of the retina; consists of opsin combined with 11-cis retinal; it is bleached by the action of light, which converts it to opsin and all-trans-retinal, and is restored in the dark by rhodogenesis; the dominant protein in the plasma membrane of rod cells.
Synonym(s): visual purple

rhodopsin

(rō-dŏp′sĭn)
n.
Any of a class of reddish, light-sensitive pigments found in the retinal rods of the eyes of terrestrial and marine vertebrates, consisting of opsin and retinal. Also called visual purple.

rho·dop·sin

(rō-dop'sin)
A red thermolabile protein found in the rods of the retina; it is bleached by the action of light, which converts it to opsin and all-trans-retinal, and is restored in the dark by rhodogenesis; the dominant protein in the plasma membrane of rod cells.
Synonym(s): visual purple.

rhodopsin

The retinal rod photoreceptor pigment. Also known as visual purple.

rhodopsin

a photochemical pigment found in the rods of the retina of the vertebrate eye. When bleached by absorbed light, rhodopsin dissociates into its two components - a pigment called RETINAL and a protein called OPSIN. This dissociation ultimately triggers an action potential and the production of nerve impulses in the ganglion cells leading to the optic nerve. Lack of rhodopsin causes night blindness.

rhodopsin 

Visual pigment contained in the outer segments of the rod cells of the retina and involved in scotopic vision. When light stimulates the retina, the chromophore of the pigment molecule '11-cis' retinal (which is vitamin A aldehyde) isomerizes to 'all-trans' retinal. This leads to other chemical transformations which carry on even in the absence of light. The first stage is prelumirhodopsin, then lumirhodopsin and finally metarhodopsin (of which there are two types). This last transformation may lead to the breakdown of the molecule into retinal and opsin. The molecule is regenerated by recombining retinal and opsin with some enzymes. The absorption spectrum of rhodopsin has a maximum around 498 nm. The isomerization from '11-cis' to 'all-trans' also gives rise to the process of transduction in which the membrane potential covering the pigment molecules in the outer segment changes towards a hyperpolarization of the cell. This is the first step in the nervous response to a light stimulation of the retina. Syn. visual purple (not used any more); erythropsin. See dark adaptation; bleaching; receptor potential; absorption spectrum; transduction.

rho·dop·sin

(rō-dop'sin) [MIM*180380]
A red thermolabile protein found in the rods of the retina.
Synonym(s): visual purple.
References in periodicals archive ?
On the other hand, all-trans retinoic acid (atRA) and calcitriol (VitD3), active metabolites of vitamins A and D, have shown to reinforce suppressive functions of Tregs.
Liu, "All-trans retinoic acid inhibits type 1 diabetes by T regulatory (Treg)-dependent suppression of interferongamma-producing T-cells without affecting Th17 cells," Diabetes, vol.
(1997) Molecular remission in PML/RAR alpha-positive acute promyelocytic leukemia by combined all-trans retinoic acid and idarubicin (AIDA) therapy.
Characterization of acute promyelocytic leukemia cases with PML-RAR[alpha]-break-fusion sites in PML exon 6: Identification of a subgroup with decreased in vitro responsiveness to all-trans retinoic acid.
All-trans retinoic acid-responsive genes identified in the human SH-SY5Y neuroblastoma cell line and their regulated expression in the nervous system of early embryos.
The next stage of research will focus on better understanding how the immune system takes retinol, the inactive form of vitamin A, and creates all-trans retinoic acid, the form of the nutrient that can activate the infected cells against the TB bacteria.
Similar findings were reported earlier in which single topical application of all-trans retinoic acid for 4 days stimulated keratinocyte proliferation increasing the number of epidermal cell layers and increasing epidermal thickness.23Another study demonstrated aromatic retinoid induced epidermal hyper-proliferation and numericalhyperplasia after oral administration of the drug in the animal model of the hairless mouse.24Increasing EGF binding capacity in several cell types after RA treatment also has been found.25 Mechanism of action of epidermal growth factor (EGF) is pre-
On the other hand, effect of SAHA is possible to increase by adding all-trans retinoic acid (ATRA, [21]), which is known to suppress Bcl-2 expression [22-25].
All-trans retinoid acid (ATRA) is a potent vitamin A derivative that has been clinically used for the treatment of acute promyelocytic leukemia [3] and skin disease [4].
The Effect of Alpha Tocopherol, All-Trans Retinol, and Retinyl Palmitate on the Nonenzymatic Lipid Peroxidation of Rod Outer Segments.
Several clinical studies have described an AML-stabilizing effect of valproic acid (VPA) in combination with all-trans retinoic acid (ATRA) and eventually cytotoxic drugs (e.g., Ara-C) [6-14].