title: Number and distribution of mouse retinal cone photoreceptors: differences between an albino (Swiss) and a pigmented (C57/BL6) strain.
abstract: We purpose here to analyze and compare the population and topography of cone photoreceptors in two mouse strains using automated routines, and to design a method of retinal sampling for their accurate manual quantification. In whole-mounted retinas from pigmented C57/BL6 and albino Swiss mice, the longwave-sensitive (L) and the shortwave-sensitive (S) opsins were immunodetected to analyze the population of each cone type. In another group of retinas both opsins were detected with the same fluorophore to quantify all cones. In a third set of retinas, L-opsin and Brn3a were immunodetected to determine whether L-opsin+cones and retinal ganglion cells (RGCs) have a parallel distribution. Cones and RGCs were automatically quantified and their topography illustrated with isodensity maps. Our results show that pigmented mice have a significantly higher number of total cones (all-cones) and of L-opsin+cones than albinos which, in turn, have a higher population of S-opsin+cones. In pigmented animals 40% of cones are dual (cones that express both opsins), 34% genuine-L (cones that only express the L-opsin), and 26% genuine-S (cones that only express the S-opsin). In albinos, 23% of cones are genuine-S and the proportion of dual cones increases to 76% at the expense of genuine-L cones. In both strains, L-opsin+cones are denser in the central than peripheral retina, and all-cones density increases dorso-ventrally. In pigmented animals S-opsin+cones are scarce in the dorsal retina and very numerous in the ventral retina, being densest in its nasal aspect. In albinos, S-opsin+cones are abundant in the dorsal retina, although their highest densities are also ventral. Based on the densities of each cone population, we propose a sampling method to manually quantify and infer their total population. In conclusion, these data provide the basis to study cone degeneration and its prevention in pathologic conditions.
authors.affiliation: Instituto Murciano de Investigación Biosanitaria-Virgen de la Arrixaca, El Palmar, Murcia, Spain; Departamento de Oftalmología, Facultad de Medicina, Universidad de Murcia, Espinardo, Murcia, Spain.
authors.forename: Arturo
authors.initials: A
authors.lastname: Ortín-Martínez
authors.affiliation: Instituto Murciano de Investigación Biosanitaria-Virgen de la Arrixaca, El Palmar, Murcia, Spain.
authors.forename: Francisco M
authors.initials: FM
authors.lastname: Nadal-Nicolás
authors.affiliation: Instituto Murciano de Investigación Biosanitaria-Virgen de la Arrixaca, El Palmar, Murcia, Spain; Departamento de Oftalmología, Facultad de Medicina, Universidad de Murcia, Espinardo, Murcia, Spain.
authors.forename: Manuel
authors.initials: M
authors.lastname: Jiménez-López
authors.affiliation: Instituto Murciano de Investigación Biosanitaria-Virgen de la Arrixaca, El Palmar, Murcia, Spain.
authors.forename: Juan J
authors.initials: JJ
authors.lastname: Alburquerque-Béjar
authors.affiliation: Instituto Murciano de Investigación Biosanitaria-Virgen de la Arrixaca, El Palmar, Murcia, Spain; Departamento de Oftalmología, Facultad de Medicina, Universidad de Murcia, Espinardo, Murcia, Spain.
authors.forename: Leticia
authors.initials: L
authors.lastname: Nieto-López
authors.affiliation: Instituto Murciano de Investigación Biosanitaria-Virgen de la Arrixaca, El Palmar, Murcia, Spain; Departamento de Oftalmología, Facultad de Medicina, Universidad de Murcia, Espinardo, Murcia, Spain.
authors.forename: Diego
authors.initials: D
authors.lastname: García-Ayuso
authors.affiliation: Instituto Murciano de Investigación Biosanitaria-Virgen de la Arrixaca, El Palmar, Murcia, Spain; Departamento de Oftalmología, Facultad de Medicina, Universidad de Murcia, Espinardo, Murcia, Spain.
authors.forename: Maria P
authors.initials: MP
authors.lastname: Villegas-Pérez
authors.affiliation: Instituto Murciano de Investigación Biosanitaria-Virgen de la Arrixaca, El Palmar, Murcia, Spain; Departamento de Oftalmología, Facultad de Medicina, Universidad de Murcia, Espinardo, Murcia, Spain.
authors.forename: Manuel
authors.initials: M
authors.lastname: Vidal-Sanz
authors.affiliation: Instituto Murciano de Investigación Biosanitaria-Virgen de la Arrixaca, El Palmar, Murcia, Spain.
authors.forename: Marta
authors.initials: M
authors.lastname: Agudo-Barriuso
mesh_terms: D000818:Animals; D002452:Cell Count / Q000379:methods; D051379:Mice; D008810:Mice, Inbred C57BL; D055355:Opsins / Q000302:isolation & purification; D017949:Retinal Cone Photoreceptor Cells / Q000166:cytology*; D013045:Species Specificity; D050819:Transcription Factor Brn-3A / Q000302:isolation & purification
chemical_list: D055355:Opsins; C494189:Pou4f1 protein, mouse; D050819:Transcription Factor Brn-3A