Topography of the retinal ganglion cell layer of Xenopus.
AUTOR(ES)
Graydon, M L
RESUMO
Cell distribution in the retinal ganglion cell layer of Xenopus laevis was studied by electron microscopy and the retinal wholemount method. Unlike the familiar stratification of the retina, the ganglion cell perikarya and their axons were localised in the same layer, but strictly segregated in alternate rows converging in a radial pattern on the optic disc. Rows of perikarya (retinal cords) were two to ten cells wide and clearly defined for a little more than half the distance between the optic disc and the ora serrata. Detailed analysis of 25% of the retinal surface showed higher cell density (about 3500 cells/mm2) in the centrodorsal region than in the periphery (about 2000 cells/mm2). The higher density regions represent a weak visual streak having no nasotemporal asymmetry. After staining with cresyl violet, the majority of cells appeared to be small (10 micron diameter) with very little Nissl substance. The cytoplasm was scant; this was confirmed by electron microscopy. The difference between the total cell count (68470 +/- 7360) and the total axon count in the optic nerve (Wilson, 1971) suggests a population of 15% non-ganglionic cells (glia and amacrine cells) in the retinal ganglion cell layer. Retinal ganglion cell topography in Xenopus may have relevance to studies on retinal growth and retinotopy. The functional significance of the weak visual streak in Xenopus is consistent with a limited need for visual acuity.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=1164453Documentos Relacionados
- Development and Stability of Positional Information in Xenopus Retinal Ganglion Cells
- Specification of Positional Information in Retinal Ganglion Cells of Xenopus: Stability of the Specified State
- Developmental control of the heat shock response in Xenopus.
- "Collective coding" of correlated cone signals in the retinal ganglion cell.
- Assessment of intraocular pressure, macular thickness, retinal nerve fiber layer, and ganglion cell layer thicknesses: ocular parameters and optical coherence tomography findings in attention-deficit/hyperactivity disorder