Unique topographic separation of two spectral classes of cones in the mouse retina

Abstract

We have found two immunologically distinguishable cone types in the retina of the mouse, each localized to two opposite halves of the eye. One cone type was labelled by the monoclonal antibody COS-1 specific to the middle-to-long wave sensitive visual pigment of the mammals, while the other type was stained by the shortwave-specific monoclonal antibody (OS-2). These results were confirmed with other antibodies directed against specific sequences of the visual pigments. As a result of the uneven distribution of the two cone types the mouse retina is divided into two fields separated by an oblique meridional line. The middlewave sensitive cones were present exclusively in the dorsal half of the mouse retina (M-field). The overwhelming majority of the shortwave sensitive cones occupied the ventral half (S-field), and only a small number was scattered among the middlewave sensitive cones in the dorsal retina. The ratio of the two cone types in the M-field corresponds to what has been found in the retina of other mammals, including rodents such as the gerbil and the rat. The S-field represents an entirely unique area with the unusually great number of shortwave sensitive cones and with the complete lack of the middlewave sensitive ones. The present study provides the structural basis for dichromacy in a rodent species considered for a long time to be monochromat. In addition, it shows that the ventral retina, containing exclusively S-cones in a relatively high density, is a unique retinal field not present in other mammalian species studied so far.

A retinitis pigmentosa GTPase regulator (RPGR)- deficient mouse model for X-linked retinitis pigmentosa (RP3)

“…4a). This defect was more pronounced at the retinal quadrants where the respective cone densities were the highest (i.e., superior retina for green cones and inferior retina for blue cones) (24). Mislocalization of cone opsins was found as early as postnatal day 20, the earliest time point examined.…”

The human blue opsin promoter directs transgene expression in short-wave cones and bipolar cells in the mouse retina.

“…Transgenepositive photoreceptor cells were identified as cone cells based on morphological criteria and colabeling with the cone-specific markers, peanut aaglutinin (PNA) lectin (24) and OS-2 antibody (18). Morphological characterization of photoreceptor cells was based on topological localization and nuclear staining pattern.…”

“…Rodent species have roddominant retinas and have been considered to be essentially monochromats (15 (17) have shown that the mouse retina demonstrates peak sensitivities in the middlewave (510 nm) and the near-ultraviolet (370 nm) ranges of the spectrum. Immunocytochemical studies with color-specific anti-opsin antibodies have further demonstrated the presence of two classes of cone photoreceptors in the mouse retina (18).…”

Cone Contacts, Mosaics, and Territories of Bipolar Cells in the Mouse Retina

“…All cones (leaving aside blue cones) are contacted by at least one Type 7 cell (coverage of 1.3). In the ventral retina of the mouse, most cones express both M-and S-opsin (Szél et al, 1992). When we mention "blue cones," we refer to the genuine blue cones that express only S-opsin and comprise Ͻ5% of mouse cones (Haverkamp et al, 2005).…”