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- Title
The topography of cone photoreceptors in the retina of a diurnal rodent, the agouti (Dasyprocta aguti).
- Authors
De Farias Rocha, Fernando Allan; Ahnelt, Peter K.; Peichl, Leo; Saito, Cézar A.; Silveira, Luiz Carlos L.; De Lima, Silene Maria A.
- Abstract
The presence, density distribution, and mosaic regularity of cone types were studied in the retina of the diurnal agouti, Dasyprocta aguti. Longwave-sensitive (L-) and shortwave-sensitive (S-) cones were detected by antibodies against the respective cone opsins. L- and S-cones were found to represent around 90 and 10% of the cone population, respectively. There was no evidence for L- and S-opsin coexpression in agouti cones. L-cone densities were highest, up to 14,000/mm², along a horizontal visual streak located about 2-3 mm dorsal to the optic nerve, and the L-cone distribution showed a dorsoventral asymmetry with higher densities in ventral (about 10,000/mm²) than in dorsal (about 4000/mm²) retinal regions. This L-cone topography parallels the agouti's ganglion cell topography. S-cones had a peak density of 1500-2000/mm² in the central retinal region but did not form a visual streak. Their distribution also showed a dorsoventral asymmetry with densities around 600/mm² in dorsal and around 1000/mm² in ventral retinal regions. The patterning of cone arrays was assessed by the density recovery profile analysis. At all eccentricities evaluated, the S-cone mosaic less efficiently packed than the L-cone mosaic. Rod densities ranged from 47,000/mm² in peripheral to 64,000/mm² in central retina, and rod:cone ratios were 4:1-9:1. The comparatively low rod density and high cone proportion appear well adapted to the diurnal lifestyle of the agouti.
- Subjects
MEDICAL geography; PHOTORECEPTORS; RETINA; IMMUNOGLOBULINS; RETINAL ganglion cells
- Publication
Visual Neuroscience, 2009, Vol 26, Issue 2, p167
- ISSN
0952-5238
- Publication type
Article
- DOI
10.1017/S095252380808098X