Microspectrophotometric and immunocytochemical identification of ultraviolet photoreceptors in geckos

• Published in: Visual neuroscience 1996-03, Vol.13 (2), p.247-256
• Main Authors: Loew, E. R., Govardovskii, V. I., Röhlich, P., Szél, Á.
• Format: Article
• Language: English
• Subjects: Animals; Biological and medical sciences; Eye and associated structures. Visual pathways and centers. Vision; Fundamental and applied biological sciences. Psychology; Gecko; Immunocytochemistry; Immunohistochemistry; Lizards - metabolism; Microchemistry; Microspectrophotometry - methods; Photoreceptor Cells - metabolism; Photoreceptor Cells - radiation effects; Retinal Pigments - analysis; Spectrophotometry, Ultraviolet; Ultraviolet photoreceptors; Ultraviolet Rays; Vertebrates: nervous system and sense organs; Visual pigments
• ISSN: 0952-5238; 1469-8714
• DOI: 10.1017/S0952523800007483

Retinas of the nocturnal geckos, Hemidactylus turcicus, Hemidactylus garnotii, and Teratoscincus scincus, were studied with microspectrophotometry and immunocytochemistry against various visual pigment epitopes to reveal UV-sensitive photoreceptors. From 6–20% of the thinner members of type C double photoreceptors, earlier believed to be blue-sensitive, were found to contain a UV-absorbing visual pigment with λmax at 363–366 nm. The pigment had bleaching and dichroic properties typical of other photoreceptor cell types of the retina. Presumptive UV-sensitive cells in retinal sections were “negatively” labeled as they did not react with either the cone-specific monoclonal antibody COS-1 or with the anti-rhodopsin polyclonal serum AO, which together labeled all of the remaining photoreceptor types (green-sensitive A singles, B doubles, and thicker members of C doubles, as well as the blue-sensitive majority of thinner members of C doubles). UV cells were moderately stained with the mAb K42–41 produced against the 5–6 loop of bovine rhodopsin, which also moderately labeled blue-sensitive cells. mAb OS-2 strongly stained all outer segments, including the UV-sensitive ones. Similarities between gecko UV visual pigments, and UV visual pigments of other vertebrates, as well as possible functional significance of these cells are discussed.