Biocytin wide‐field bipolar cells in rabbit retina selectively contact blue cones

Abstract

The biocytin wide-field bipolar cell in rabbit retina is a sparsely populated ON cone bipolar cell with a broad dendritic arbor that does not contact all cones in its dendritic field. The purpose of our study was to identify the cone types that this cell contacts. We identified the bipolar cells by selective uptake of biocytin, labeled the cones with peanut agglutinin and then used antibodies against blue cone opsin and red-green cone opsin to identify the individual cone types. The biocytin-labeled cells selectively contacted cones whose outer segments stained for blue cone opsin and avoided cones that did not. We conclude that the biocytin wide-field bipolar cell is an ON blue cone bipolar cell in the rabbit retina and is homologous to the blue cone bipolar cells that have been previously described in primate, mouse, and ground squirrel retinas.

Physiology and Morphology of Color-Opponent Ganglion Cells in a Retina Expressing a Dual Gradient of S and M Opsins

“…This suggests that S input to the opponent cells is processed by a retinal pathway with high relative gain. Presumably this pathway involves S−ON bipolar cells (Mariani, 1984; Kouyama and Marshak, 1992; Calkins et al, 1998; Haverkamp et al, 2005; Li and DeVries, 2006; MacNeil and Gaul, 2008). Second, opponent cells generally received smaller amounts of rod input than horizontal cells from the same retinal regions.…”

“…Dendritic field diameters are smaller than the physiologically characterized diameters, although clearly the exact relation depends on the criterion used to define the physiological diameters. In dichromatic mammals and primates, S−ON cone bipolar cells have long and meandering dendrites and axons (Mariani, 1984; Kouyama and Marshak, 1992; Haverkamp et al, 2005; MacNeil and Gaul, 2008), which could provide a mechanism for opponent ganglion cells to collect input from S cones located in regions adjacent to their dendritic fields. The relationship in the relative size between physiologically measured receptive field and anatomically measured dendritic field that we observed is roughly consistent with that found for other ganglion cell types, such as brisk-transient ganglion cells (Borghuis et al, 2008).…”

“…The S+/M− cells probably receive their input from S−ON bipolar cells, whose existence in mammals is well-established (Mariani, 1984; Kouyama and Marshak, 1992; Calkins et al, 1998; Herr et al, 2003; Schein et al, 2004; Haverkamp et al, 2005; Li and DeVries, 2006; MacNeil and Gaul, 2008). The M-antagonism might arise at the outer retina, as has been suggested for primate (Dacey et al, 1996; Dacey, 2000; Field et al, 2007; Packer et al, 2007; Davenport et al, 2008), and/or from amacrine inhibition driven by an M−ON bipolar cell (Li and DeVries, 2006).…”

Short-wavelength cone-opponent retinal ganglion cells in mammals

“…Type wb cells were also labeled by uptake of biocytin injected into the vitreous humor and visualized with avidin-fluorescein. Their dendrites contacted 2–7 S-cones identified with antibody to S-opsin (MacNeil & Gaul, 2008). …”

Maximizing contrast resolution in the outer retina of mammals

“…Even in trichromatic primates, inputs to the horizontal cells are achromatic (Dacey 1999; Packer and Dacey 2002). Further, all but one of the bipolar cell types are achromatic (MacNeil and Gaul 2008; Wässle et al 2009). Our analysis is targeted towards such simpler achromatic systems, and the results may not be applicable to more complex systems, such as the cold-blooded vertebrates, that express spectrally selective horizontal cells (Twig et al 2003).…”