Visual pigments and opsin expression in the juveniles of three species of fish (rainbow trout, zebrafish, and killifish) following prolonged exposure to thyroid hormone or retinoic acid
- Authors
- Suliman, T., and Flamarique, I.N.
- ID
- ZDB-PUB-130710-118
- Date
- 2014
- Source
- The Journal of comparative neurology 522(1): 98-117 (Journal)
- Registered Authors
- Keywords
- photoreceptor, retina, immunohistochemistry, in-situ hybridization, microspectrophotometry
- MeSH Terms
-
- Animals
- Fishes/anatomy & histology
- Fishes/growth & development
- Fishes/metabolism*
- Fundulidae/anatomy & histology
- Fundulidae/growth & development
- Fundulidae/metabolism
- Immunohistochemistry
- In Situ Hybridization
- Microspectrophotometry
- Oncorhynchus mykiss/anatomy & histology
- Oncorhynchus mykiss/growth & development
- Oncorhynchus mykiss/metabolism
- Opsins/metabolism*
- Retina/anatomy & histology
- Retina/growth & development
- Retina/metabolism*
- Retinal Cone Photoreceptor Cells/metabolism
- Retinal Pigments/metabolism*
- Retinal Rod Photoreceptor Cells/metabolism
- Species Specificity
- Thyroid Hormones/metabolism*
- Thyroid Hormones/pharmacology
- Tretinoin/metabolism*
- Tretinoin/pharmacology
- Zebrafish/anatomy & histology
- Zebrafish/growth & development
- Zebrafish/metabolism
- PubMed
- 23818308 Full text @ J. Comp. Neurol.
Thyroid hormone (TH) and retinoic acid (RA) are powerful modulators of photoreceptor differentiation during vertebrate retinal development. In the embryos and young juveniles of salmonid fishes and rodents, TH induces switches in opsin expression within individual cones, a phenomenon that also occurs in adult rodents following prolonged (12 week) hypothyroidism. Whether changes in TH levels also modulate opsin expression in the differentiated retina of fish is unknown. Like TH, RA is essential for retinal development, but its role in inducing opsin switches, if any, has not been studied. Here, we investigate the action of TH and RA on single cone opsin expression in juvenile rainbow trout, zebrafish and killifish, and on the absorbance of visual pigments in rainbow trout and zebrafish. Prolonged TH exposure increased the wavelength of maximum absorbance (λmax) of the rod, and the medium (M, green) and long (L, red) wavelength visual pigments in all fish species examined. However, unlike the opsin switch that occurred following TH exposure in the single cones of small juvenile rainbow trout (alevin), opsin expression in large juvenile rainbow trout (smolt), zebrafish or killifish remained unchanged. RA did not induce any opsin switches nor change the visual pigment absorbance of photoreceptors. Neither ligand altered cone photoreceptor densities. We conclude that RA has no effect on opsin expression or visual pigment properties in the differentiated retina of these fishes. In contrast, TH affected both single cone opsin expression and visual pigment absorbance in the rainbow trout alevin but only visual pigment absorbance in the smolt, and in zebrafish. The latter results could be explained by a combination of opsin switches and chromophore shifts from vitamin A1 to A2.