Mapping kainate activation of inner neurons in the rat retina

Authors

  • Lisa Nivison-Smith,

    1. School of Optometry and Vision Science, University of New South Wales, Sydney, New South Wales, 2052, Australia
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  • Daniel Sun,

    1. Department of Ophthalmology, Massachusetts Eye & Ear Infirmary, Boston, Massachusetts 02114
    2. Department of Optometry and Vision Science, University of Auckland, Auckland, 1142, New Zealand
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  • Erica L. Fletcher,

    1. Department of Anatomy and Neuroscience, University of Melbourne, Parkville, 3010, Australia
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  • Robert E. Marc,

    1. University of Utah School of Medicine, Department of Ophthalmology, University of Utah, Salt Lake City, Utah 84113
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  • Michael Kalloniatis

    Corresponding author
    1. School of Optometry and Vision Science, University of New South Wales, Sydney, New South Wales, 2052, Australia
    2. Department of Ophthalmology, Massachusetts Eye & Ear Infirmary, Boston, Massachusetts 02114
    3. Department of Anatomy and Neuroscience, University of Melbourne, Parkville, 3010, Australia
    4. Centre for Eye Health, Sydney, New South Wales, 2052, Australia
    • Centre for Eye Health, University of New South Wales, Sydney, 2052, NSW, Australia

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Abstract

Kainate receptors mediate fast, excitatory synaptic transmission for a range of inner neurons in the mammalian retina. However, allocation of functional kainate receptors to known cell types and their sensitivity remains unresolved. Using the cation channel probe 1-amino-4-guanidobutane agmatine (AGB), we investigated kainate sensitivity of neurochemically identified cell populations within the structurally intact rat retina. Most inner retinal neuron populations responded to kainate in a concentration-dependent manner. OFF cone bipolar cells demonstrated the highest sensitivity of all inner neurons to kainate. Immunocytochemical localization of AGB and macromolecular markers confirmed that type 2 bipolar cells were part of this kainate-sensitive population. The majority of amacrine (ACs) and ganglion cells (GCs) showed kainate responses with different sensitivities between major neurochemical classes (γ-aminobutyric acid [GABA]/glycine ACs > glycine ACs > GABA ACs; glutamate [Glu]/weakly GABA GCs > Glu GCs). Conventional and displaced cholinergic ACs were highly responsive to kainate, whereas dopaminergic ACs do not appear to express functional kainate receptors. These findings further contribute to our understanding of neuronal networks in complex multicellular tissues. J. Comp. Neurol. 521:2416–2438, 2013. © 2013 Wiley Periodicals, Inc.

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