Morphogenesis and territorial coverage by isolated mammalian retinal ganglion cells

• Published in: The Journal of neuroscience 1991-05, Vol.11 (5), p.1440-1457
• Main Authors: Montague, PR, Friedlander, MJ
• Format: Article
• Language: English
• Subjects: Animals; Axons - physiology; Axons - ultrastructure; Biological and medical sciences; Cats; Cells, Cultured; Culture Techniques - methods; Dendrites - physiology; Dendrites - ultrastructure; Eye and associated structures. Visual pathways and centers. Vision; Fundamental and applied biological sciences. Psychology; Morphogenesis; Retinal Ganglion Cells - cytology; Retinal Ganglion Cells - physiology; Time Factors; Vertebrates: nervous system and sense organs
• ISSN: 0270-6474; 1529-2401
• DOI: 10.1523/jneurosci.11-05-01440.1991

Identified retinal ganglion cells were isolated from postnatal cat retinas and their dendrites were removed by trituration and centrifugation. The denuded cells were placed in a cell culture system and allowed to reexpress dendritic arbors in the absence of afferent input, target tissue, and interactions with neighboring ganglion cells. The retinal ganglion cells were grown above a feeder layer of astrocytes on glass coverslips equipped with paraffin pedestals. The spatial patterns of the reexpressed neurites were quantitatively analyzed using a number of measures, including an estimate of the Hausdorff dimension, H, which was used as a scale-independent metric for how well the neurite patterns filled in a restricted spatial domain. As assessed by the estimation of the Hausdorff dimensions, the neurites from a single cell achieve uniform coverage of a restricted territory independent of the total neurite length or the total number of inter-branch-point segments. A comparison with H values of ganglion cells from the intact retina revealed a similar trend. These results suggest that these cultured ganglion cells can express an intrinsic growth strategy for the uniform coverage of a restricted territory. The arbors expressed in the culture system displayed a limited range of diameters and exhibited morphology similar to the alpha-, beta-, and gamma-ganglion cells of the intact retina in the absence of afferent input or the influences of neighboring cells and target tissue. Time-lapse video data revealed that individual cultured cells showed extensive dendritic remodeling during their growth; however, after about 3 d in culture, this remodeling did not appreciably affect the territorial coverage of a cell. In the intact retina, the existence of dendritic sheets that independently and uniformly sample visual space may result from this intrinsic ability to elaborate dendrites that uniformly cover or fill in a restricted territory.