The topography of cytogenesis in the developing retina of the cat

Abstract

We have studied the pattern of cytogenesis in the developing retina of the cat, by observing mitotic cells in sections and whole mounts of the retinae of animals between the ages of E (embryonic day) 29 and P (postnatal day) 20. The whole mounts were prepared with the mitotic or ventricular layer uppermost; all of the mitotic cells in this layer could then be surveyed. In retinae from animals up to E46, mitotic cells were present in the ventricular layer at densities of 1000 to 3000 cells/mm2, and their density did not vary consistently with position in the retina. Thus cell division occurs throughout the retina at these ages, with an approximately constant spatial density. By E50, cytogenesis begins to cease and there is a significant pattern to the cessation. Initially, mitotic activity ceases over a small region of retina at the site of the developing area centralis. The nonmitotic area then increases with age, comprising the central 30 to 50% of the retina at birth and the whole of the retina by PlO. The pattern of cessation of cytogenesis is closely coincident in space and time with the development of the outer plexiform layer and the maturation of the ganglion cell layer described in previous studies. These patterns presumably contribute to the regional variations in structure apparent in the adult retina.

Maturational gradients in the retina of the ferret

“…Mitotic activity in the cat retina ceases first in the center, creating a cold spot that progresses to the retinal periphery during the following 3 weeks (Rapaport and Stone, 1983). We have found a similarly enlarging cold spot of mitotic activity in the developing ferret retina by using a different labelling procedure and criterion (immunopositive cells at the ventricular surface), but we failed to find conclusive evidence that this cold spot is initiated at the area centralis.…”

“…In the cat, proliferation of retinal cells ceases first in the region of the area centralis, as evidenced by the absence of mitotic figures at the outer limiting membrane (the ventricular surface) of the retina (Rapaport and Stone, 1983). We have examined the cessation of proliferative activity in the developing ferret retina by using a monoclonal antibody (MIB-1) to a nuclear protein (Ki-67) that is associated with the cell cycle.…”

Radiation-induced apoptosis in developing mouse retina exhibits dose-dependent requirement for ATM phosphorylation of p53

“…To avoid variation in the counts due to a difference in developmental stage inside the retinal tissue, the retinal central area (close to the optic nerve), where the retinal tissue develops first, was the location for counting. 45,46 The results were first analyzed among animals from the same litter. Histograms show the mean plus standard error of the mean (S.E.M.)…”

Astrocyte Proliferation During Development of the Human Retinal Vasculature

“…By 10 WG in the human, when the optic cup has formed, the ventricular layer is juxtaposed to the retinal pigmented epithelium (Rapaport and Stone, 1982 ;Rapaport and Stone, 1983). The incipient fovea (site of the future foveal depression) is the first region of the retina to cease proliferation and develop a full complement of differentiated neurons.…”