Ectopic Photoreceptors and Cone Bipolar Cells in the Developing and Mature Retina

Abstract

An antibody against recoverin, the calcium-binding protein, labels photoreceptors, cone bipolar cells, and a subpopulation of cells in the ganglion cell layer. In the present study, we sought to establish the origin and identity of the cells expressing recoverin in the ganglion cell layer of the rat retina. By double labeling with rhodopsin, we demonstrate that early in development some of the recoverin-positive cells in the ganglion cell layer are photoreceptors. During the first postnatal week, these rhodopsin-positive cells are eliminated from the ganglion cell layer, but such neurons remain in the inner nuclear layer well into the first postnatal month. Another contingent of recoverin-positive cells, with morphological features equivalent to those of bipolar cells, is present in the postnatal retina, and approximately 50% of these neurons survive to maturity. The incidence of such cells in the ganglion cell layer was not affected by early transection of the optic nerve, a manipulation that causes rapid loss of retinal ganglion cells. These recoverin-positive cells were not double-labeled by cell-specific markers expressed by photoreceptors, rod bipolar cells, or horizontal and amacrine cells. Based on their staining with recoverin and salient morphological features, these ectopic profiles in the ganglion cell layer are most likely cone bipolar cells. Collectively, the results provide evidence for photoreceptors in the ganglion cell and inner nuclear layers of the developing retina, and a more permanent subpopulation of cone bipolar cells displaced to the ganglion cell layer.

Rod differentiation factor NRL activates the expression of nuclear receptor NR2E3 to suppress the development of cone photoreceptors

“…The presence of ectopic S-opsin cells in the INL of rd7 and Nrl −/− retinas is reminiscent of previous findings showing opsin-like immunoreactive cells in the developing retina [25]. Our study reveals the presence of ectopic S-opsin positive cells that persist and survive in the adult retinas from Nrl −/− and rd7 mice.…”

Patterns of cell proliferation and rod photoreceptor differentiation in shark retinas

“…Opsin-like-ir cells that express several phenotypic characteristics of rods have previously been noted in the INL of the developing rat retina (Barnstable, 1982;Araki et al, 1988). More recently, a few rhodopsin-positive profiles were observed in both the INL and the prospective GCL of developing rats (Gü nhan- Agar et al, 2000;Gü nhan et al, 2003). As in sharks (present results), ectopic rod opsin expression in the rat is transient.…”

“…It has been suggested that these cells may either degenerate or undergo phenotypic conversion during subsequent maturation of the retina (Araki et al, 1988). Indeed, these opsin-like cells were interpreted as a contingent of photoreceptors that fail to recognize a signal to stop migrating when they arrive at the photoreceptor layer, and that their early elimination from the GCL and later from the INL probably reflects the failure of these cells to form functional synapses in inappropriate retinal layers (Gü nhan et al, 2003).…”

Neuropeptide Y Receptors Y1and Y2are Present in Neurons and Glial Cells in Rat Retinal Cells in Culture

“…Rhodopsin is a photopigment found in rods, the most common type of photoreceptor in the retina. 34 Bipolar cells were identified by Protein Kinase C (PKC) alfa. [34][35][36] Different subpopulations of amacrine cells were identified by calcium binding proteins: calbindin, calretinin, and parvalbumin.…”

“…34 Bipolar cells were identified by Protein Kinase C (PKC) alfa. [34][35][36] Different subpopulations of amacrine cells were identified by calcium binding proteins: calbindin, calretinin, and parvalbumin. [37][38][39][40] The same proteins may also be present in ganglion cells; however, a more specific marker of ganglion cells was used, Brn3a.…”