Maturational gradients in the retina of the ferret

Abstract

In the present set of studies, we have examined the site for the initiation of retinal maturation in the ferret. A variety of maturational features across the developing inner and outer retina were examined by using standard immunohistochemical, carbocyanine dye labelling, and Nissl-staining techniques, including 1) two indices of early differentiation of the first-born retinal ganglion cells, the presence of beta-tubulin and of neuron-specific enolase; 2) the receding distribution of chondroitin sulfate proteoglycans within the inner retina; 3) the distribution of the first ganglion cells to grow axons along the optic nerve; 4) the emergence of the inner plexiform layer; 5) the emergence of the outer plexiform layer and 6) the onset of synaptophysin immunoreactivity within it; 7) the differentiation of calbindin-immunoreactive horizontal cells; and 8) the cessation of proliferative activity at the ventricular surface. Although we were able to define distinct maturational gradients that are associated with many of these features of inner and outer retinal development (each considered in detail in this report), with dorsal retina maturing before ventral retina, and with peripheral retina maturing last, none showed a clear initiation in the region of the developing area centralis. Rather, maturation began in the peripapillary retina dorsal to the optic nerve head, which is consistent with previous studies on the topography of ganglion cell genesis in the ferret. These results make clear that the order of retinal maturation and the formation of the area centralis are not linked, at least not in the ferret.

Spatial and temporal patterns of apoptosis during differentiation of the retina in the turtle

“…Thus, differentiation starts in a region dorsal to the optic nerve head (DC region) and then progresses to the peripheral retina (unpublished observations). Similar patterns have been observed in other vertebrates (Straznicky and Gaze 1971;Prada et al 1991;Reese et al 1996;Marcus et al 1999). The possibility of a relationship between cell death and cell differentiation in the turtle retina must therefore be taken into account, and would merit investigation…”

Eye development and retinal differentiation in an altricial fish species, the senegalese sole (Solea senegalensis, Kaup 1858)

“…In the Senegalese sole retina, a central‐to‐peripheral sweep of histogenesis and cell differentiation was evident. Thus, the emergence of the plexiform layers, the detection of the first postmitotic cells, and the appearance of the cell neurochemical markers started in the central retina spreading to more peripheral regions, as has been described for other teleosts (Johns and Easter, '77; Sharma and Ungar, '80; Vecino et al, '93; Hagedorn et al, '98; Vecino, '98; Doldan et al, '99; Hu and Easter, '99; Schmitt and Dowling, '99; Peterson et al, 2001; Candal et al, 2005a, 2008; Kitambi and Malicki, 2008; Bejarano‐Escobar et al, 2009) and other vertebrates (Young, '85; Prada et al, '91; Snow and Robson, '95; Reese et al, '96; Francisco‐Morcillo et al, 2005, 2006). Additionally, we found that the expression of different markers, such as Isl1 and CR, follows a vitreal‐to‐scleral gradient of appearance, as has been described for the developmental expression of CR in the brown trout (Vecino et al, '93; Candal et al, 2005b) and turbot retina (Doldán et al, '99).…”

Expression of classic cadherins and δ-protocadherins in the developing ferret retina

“…Peripheral regions of the retina show expression patterns similar to central ones (data not shown). Nevertheless, a maturational delay of around 10 to 15 days has been reported for extreme peripheral parts of the ferret retina [35]. Dorsoventral differences of ganglion cell distribution have also been reported [36].…”