Cell death in the developing retinal ganglion cell layer of the wallaby Setonix brachyurus. 1987

S A Dunlop, and L D Beazley
Department of Psychology, University of Western Australia, Nedlands.

The distribution and number of dying cells in the developing retinal ganglion cell layer of the wallaby Setonix brachyurus were assessed by using cresyl violet stained tissue. The density of dying cells has been expressed per 100 live cells for the entire retinal surface, data being presented as a grid of 500 micron squares. For statistical analysis, retinae were divided into 8 regions; dorsal, ventral, nasal, and temporal quadrants, each further divided into center and periphery. This method allowed comparison of the extent of cell death at different retinal locations as the high density area centralis of live cells developed temporal to the optic disk from 60 days onward. Between 30 and 70 days, dying cells were seen across the entire retina; beyond 100 days very few were seen. Initially, there was a significantly higher incidence of dying cells in the central retina compared to the periphery, whereas from 50 days this situation was reversed. Analysis of the central retina before and during area centralis formation consistently indicated a significantly lower number of dying cells per 100 live cells in temporal compared to other retinal quadrants. This differential pattern suggests that cell death lowers live cell densities less in the emerging area centralis than elsewhere, and therefore must play a part in establishing live cell density gradients. However, we cannot exclude the possibility that other factors are also instrumental. Indeed, factors such as areal growth (Beazley et al., in press) presumably operate at later stages since live cell density gradients continue to be accentuated even after cell death is complete. Numbers of dying cells peaked by 50 days, reaching approximately 1% of the live cell population. At this stage, counts were also maximal for live cells with values up to 30% above the adult range.

UI MeSH Term Description Entries
D007614 Macropodidae A family of herbivorous leaping MAMMALS of Australia, New Guinea, and adjacent islands. Members include kangaroos, wallabies, quokkas, and wallaroos. Kangaroos,Macropus,Petrogale,Quokkas,Setonix,Wallabies,Wallabies, Rock,Wallaroo,Macropus robustus,Kangaroo,Petrogales,Quokka,Rock Wallabies,Rock Wallaby,Wallaby,Wallaby, Rock,Wallaroos
D008394 Marsupialia An infraclass of MAMMALS, also called Metatheria, where the young are born at an early stage of development and continue to develop in a pouch (marsupium). In contrast to Eutheria (placentals), marsupials have an incomplete PLACENTA. Metatheria,Marsupials,Marsupial
D012160 Retina The ten-layered nervous tissue membrane of the eye. It is continuous with the OPTIC NERVE and receives images of external objects and transmits visual impulses to the brain. Its outer surface is in contact with the CHOROID and the inner surface with the VITREOUS BODY. The outer-most layer is pigmented, whereas the inner nine layers are transparent. Ora Serrata
D002452 Cell Count The number of CELLS of a specific kind, usually measured per unit volume or area of sample. Cell Density,Cell Number,Cell Counts,Cell Densities,Cell Numbers,Count, Cell,Counts, Cell,Densities, Cell,Density, Cell,Number, Cell,Numbers, Cell
D002470 Cell Survival The span of viability of a cell characterized by the capacity to perform certain functions such as metabolism, growth, reproduction, some form of responsiveness, and adaptability. Cell Viability,Cell Viabilities,Survival, Cell,Viabilities, Cell,Viability, Cell
D000375 Aging The gradual irreversible changes in structure and function of an organism that occur as a result of the passage of time. Senescence,Aging, Biological,Biological Aging
D000818 Animals Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA. Animal,Metazoa,Animalia
D012165 Retinal Ganglion Cells Neurons of the innermost layer of the retina, the internal plexiform layer. They are of variable sizes and shapes, and their axons project via the OPTIC NERVE to the brain. A small subset of these cells act as photoreceptors with projections to the SUPRACHIASMATIC NUCLEUS, the center for regulating CIRCADIAN RHYTHM. Cell, Retinal Ganglion,Cells, Retinal Ganglion,Ganglion Cell, Retinal,Ganglion Cells, Retinal,Retinal Ganglion Cell

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