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K. Farrow, T. J. Viney, B. Roska; The Anatomy and Physiology of A17 Cells in the Mouse Retina. Invest. Ophthalmol. Vis. Sci. 2008;49(13):1420.
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© ARVO (1962-2015); The Authors (2016-present)
To determine the anatomy, physiology and response properties of the A17 cell in the mouse retina. Night (scotopic) vision is mediated by a retinal circuit that distributes rod mediated light responses to cone bipolar cell terminals via rod bipolar and AII amacrine cells. At the base of this circuit the A17 cell provides feedback to rod bipolar cell terminals. This feedback has been implicated in modulating the gain and timing of rod mediated vision, as well as shaping the spatial response properties of AII amacrine cells.
Targeted patch-clamp recordings in the whole mount retina were made from A17 cells genetically labelled with green flourescent protein. The excitatory and inhibitory synaptic currents were measured in response to flashes of light and the anatomy of each recorded cell was reconstructed using confocal microscopy. We recorded both genetically labelled cells in the amacrine cell layer as well as those with displaced cell bodies.
All recorded cells responded to the onset of light with a sustained excitatory current, lasting the duration of the stimulus. In addition, a transient inhibitory current was observed at light off. Qualitatively similar currents were recorded under dark adapted conditions and after prolonged exposure to a bright background light. In addition, the response properties of displaced cells were indistinguishable from those found in the amacrine cell layer. Anatomically these cells were very large. They had long sparse punctated dendtrites that stratified in the ON sublaminar adjecent to the ganglion cell bodies.
These results demonstrate that the displaced and non-displaced genetically labelled cells display the same response properties, implying that they are the same cell type, A17. In addition, in appears that the A17 cell in the mouse retina receives cone mediated light responses.
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