Morphometry and distribution of displaced dopaminergic cells in rat retina

Martin-Martinelli, Elisabeth; Savy, Claudine; Nguyen‐Legros, Jeanine

doi:10.1016/0361-9230(94)90020-5

Cited by 17 publications

(11 citation statements)

References 32 publications

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“…1a) and in retinal sections confirm the general descriptions provided by others for the mouse retina (Versaux-Botteri et al, 1984;Wulle and Schnitzer, 1989;Gustincich et al, 1997). These cells are situated almost entirely within the inner nuclear layer (INL) at the boundary with the inner plexiform layer (IPL), with less than 1% being displaced into the ganglion cell layer (GCL), as in the rat retina (Martin-Martinelli et al, 1994), and to be contrasted with the carnivore retina in which nearly a third are found in the GCL (Peichl, 1991). They have relatively large somas ranging from 9 -16 m in diameter (Fig.…”

Section: Dopaminergic Amacrine Cell Density and Distributionsupporting

confidence: 86%

Determinants of the exclusion zone in dopaminergic amacrine cell mosaics

Raven

Eglen

Ohab

et al. 2003

J of Comparative Neurology

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A fundamental organizing feature of the retina is the presence of regularly spaced distributions of neurons, yet we have little knowledge of how this patterning emerges during development. Among these retinal mosaics, the spatial organization of the dopaminergic amacrine cells is unique: using nearest-neighbor and Vornoi domain analysis, we found that the dopaminergic amacrine cells were neither randomly distributed, nor did they achieve the regularity documented for other retinal cell types. Autocorrelation analysis revealed the presence of an exclusion zone surrounding individual dopaminergic amacrine cells and modeling studies confirmed this organization, as the mosaic could be simulated by a minimal distance spacing rule defined by a broad set of parameters. Experimental studies determined the relative contributions of tangential dispersion, fate determination, and cell death in the establishment of this exclusion zone. Clonal boundary analysis and simulations of proximity-driven movement discount tangential dispersion, while data from bcl-2 overexpressing mice rule out feedback-inhibitory fate-deterministic accounts. Cell death, by contrast, appears to eliminate dopaminergic amacrine cells that are within close proximity, thereby establishing the exclusion zone surrounding individual cells and in turn creating their mosaic regularity.

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Section: Dopaminergic Amacrine Cell Density and Distributionsupporting

confidence: 86%

Determinants of the exclusion zone in dopaminergic amacrine cell mosaics

Raven

Eglen

Ohab

et al. 2003

J of Comparative Neurology

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“…In the Sprague Dawley rat retina, a very small number (<10 per retina) of DA cells are displaced to the GCL [14]. To assess whether our spiking sustained ON amacrines were merely displaced DA cells, we randomly picked 9 cells (2 monostratified, 1 bistratified, and 6 polyaxonal) for immunostaining against the DA cell marker tyrosine hydroxylase.…”

Section: Resultsmentioning

confidence: 99%

All Spiking, Sustained ON Displaced Amacrine Cells Receive Gap-Junction Input from Melanopsin Ganglion Cells

et al. 2015

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SUMMARY Retinal neurons exhibit sustained vs. transient light responses, which are thought to encode low- and high-frequency stimuli respectively. This dichotomy has been recognized since the earliest intracellular recordings from the 1960s, but the underlying mechanisms are not yet fully understood. We report that in the ganglion cell layer of rat retinas, all spiking amacrine interneurons with sustained ON photoresponses receive gap-junction input from intrinsically photosensitive retinal ganglion cells (ipRGCs), recently discovered photoreceptors that specialize in prolonged irradiance detection. We have identified three morphological varieties of such ipRGC-driven displaced amacrine cells: 1) monostratified cells with dendrites terminating exclusively in sublamina S5 of the inner plexiform layer; 2) bistratified cells with dendrites in both S1 and S5; and 3) polyaxonal cells with dendrites and axons stratifying in S5. Most of these amacrine cells are wide-field, although some are medium-field. The three classes respond to light differently, suggesting they probably perform diverse functions. These results demonstrate that ipRGCs are a major source of tonic visual information within the retina and exert widespread intraretinal influence. They also add to recent evidence that ganglion cells signal not only to the brain.

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“…The percentage of dopaminergic amacrine cells situated in the GCL is known to vary among species. For example, less than 1% is positioned in the GCL of the rat's retina (Martin-Martinelli et al, 1994), whereas around 40% are so positioned in the dog's retina (Peichl, 1991). Indeed, within the dog's retina, their proportion varies across the retina from 10% to 85%, with no consistent pattern (Peichl, 1991).…”

Section: Discussionmentioning

confidence: 99%

Dopaminergic amacrine cells in the inner nuclear layer and ganglion cell layer comprise a single functional retinal mosaic

Eglen

Raven

Tamrazian

et al. 2003

J of Comparative Neurology

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Many types of retinal neuron are distributed in an orderly manner across the surface of the retina. Indeed, the existence of such regularity amongst a population of neurons, termed a retinal mosaic, may be a defining feature of functionally independent types of retinal neuron. We have examined the spatial distribution of dopaminergic amacrine cells in the ferret retina both in the inner nuclear layer (INL) and in the ganglion cell layer (GCL) to determine whether the cells in each layer form an independent retinal mosaic as evidence of whether they should be considered as two separate types. Ferret retinas contain approximately 1,900 dopaminergic amacrine cells, of which 27% are located in the GCL, and the rest in the INL. Based on analysis of their Voronoi domains as well as autocorrelation analysis and tests for complete spatial randomness, we found that the distribution of INL cells was statistically regular, while that of the GCL cells was not. However, by using cross-correlation analysis, these two groups of cells were found to be spatially dependent: an exclusion zone was detected in the cross-correlogram of roughly the same size as that found in the autocorrelograms of both INL and GCL cells. Such a pattern would be expected if dopaminergic amacrine cells in the INL and GCL were members of a single regular population differing only in their somatic depth. By using computer simulations, we tested this hypothesis directly, confirming that a random assignment of 27% from the total population produces cross-correlograms that are indistinguishable from those of the biological mosaics. We conclude, therefore, that the cells in the two layers form a single functional population; those in the GCL appear to be misplaced. Somatic positioning with respect to depth within the retina is not, by itself, a reliable guide for functional classification.

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Morphometry and distribution of displaced dopaminergic cells in rat retina

Cited by 17 publications

References 32 publications

Determinants of the exclusion zone in dopaminergic amacrine cell mosaics

Determinants of the exclusion zone in dopaminergic amacrine cell mosaics

All Spiking, Sustained ON Displaced Amacrine Cells Receive Gap-Junction Input from Melanopsin Ganglion Cells

Dopaminergic amacrine cells in the inner nuclear layer and ganglion cell layer comprise a single functional retinal mosaic

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