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Connexin36 is required for gap junctional coupling of most ganglion cell subtypes in the mouse retina

Authors

  • Feng Pan,

    1. Department of Ophthalmology, New York University School of Medicine, New York, New York 10016
    2. Department of Physiology and Neuroscience, New York University School of Medicine, New York, New York 10016
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  • David L. Paul,

    1. Department of Neurobiology, Harvard Medical School, Boston, Massachusetts 02115
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  • Stewart A. Bloomfield,

    1. Department of Ophthalmology, New York University School of Medicine, New York, New York 10016
    2. Department of Physiology and Neuroscience, New York University School of Medicine, New York, New York 10016
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  • Béla Völgyi

    Corresponding author
    1. Department of Ophthalmology, New York University School of Medicine, New York, New York 10016
    • Department of Ophthalmology, NYU School of Medicine, 550 First Avenue, New York, NY 10016
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Abstract

Converging evidence indicates that electrical synaptic transmission via gap junctions plays a crucial role in signal processing in the retina. In particular, amacrine and ganglion cells express numerous gap junctions, resulting in extensive electrical networks in the proximal retina. Both connexin36 (Cx36) and connexin45 (Cx45) subunits are widely distributed in the inner plexiform layer (IPL) and therefore are likely contribute to gap junctions formed by a number of ganglion cell subtypes. In the present study, we used the gap junction-permeant tracer Neurobiotin to compare the coupling pattern of different ganglion cell subtypes in wild-type (WT) and Cx36 knockout (KO) mouse retinas. We found that homologous ganglion-to-ganglion cell coupling was lost for two subtypes after deletion of Cx36, whereas two other ganglion cell subtypes retained homologous coupling in the KO mouse. In contrast, deletion of Cx36 resulted in a partial or complete loss of ganglion-to-amacrine cell heterologous coupling in 9 of 10 ganglion cell populations studied. Overall, our results indicate that Cx36 is the predominant subunit of gap junctions in the proximal mouse retina, expressed by most ganglion cell subtypes, and thereby likely plays a major role in the concerted activity generated by electrical synapses. J. Comp. Neurol. 518:911–927, 2010. © 2009 Wiley-Liss, Inc.

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