title: Imaging Ca2+ dynamics in cone photoreceptor axon terminals of the mouse retina.
abstract: Retinal cone photoreceptors (cones) serve daylight vision and are the basis of color discrimination. They are subject to degeneration, often leading to blindness in many retinal diseases. Calcium (Ca(2+)), a key second messenger in photoreceptor signaling and metabolism, has been proposed to be indirectly linked with photoreceptor degeneration in various animal models. Systematically studying these aspects of cone physiology and pathophysiology has been hampered by the difficulties of electrically recording from these small cells, in particular in the mouse where the retina is dominated by rod photoreceptors. To circumvent this issue, we established a two-photon Ca(2+) imaging protocol using a transgenic mouse line that expresses the genetically encoded Ca(2+) biosensor TN-XL exclusively in cones and can be crossbred with mouse models for photoreceptor degeneration. The protocol described here involves preparing vertical sections ("slices") of retinas from mice and optical imaging of light stimulus-evoked changes in cone Ca(2+) level. The protocol also allows "in-slice measurement" of absolute Ca(2+) concentrations; as the recordings can be followed by calibration. This protocol enables studies into functional cone properties and is expected to contribute to the understanding of cone Ca(2+) signaling as well as the potential involvement of Ca(2+) in photoreceptor death and retinal degeneration.
authors.affiliation: Institute for Ophthalmic Research, University of Tübingen; Graduate School of Cellular & Molecular Neuroscience, University of Tübingen.
authors.forename: Manoj
authors.initials: M
authors.lastname: Kulkarni
authors.affiliation: Institute for Ophthalmic Research, University of Tübingen; Bernstein Centre for Computational Neuroscience, University of Tübingen.
authors.forename: Timm
authors.initials: T
authors.lastname: Schubert
authors.affiliation: Institute for Ophthalmic Research, University of Tübingen; Graduate School of Cellular & Molecular Neuroscience, University of Tübingen; Bernstein Centre for Computational Neuroscience, University of Tübingen.
authors.forename: Tom
authors.initials: T
authors.lastname: Baden
authors.affiliation: Molecular Genetics Laboratory, University of Tübingen; Centre for Ophthalmology, University of Tübingen.
authors.forename: Bernd
authors.initials: B
authors.lastname: Wissinger
authors.affiliation: Institute for Ophthalmic Research, University of Tübingen; Graduate School of Cellular & Molecular Neuroscience, University of Tübingen; Bernstein Centre for Computational Neuroscience, University of Tübingen; thomas.euler@cin.uni-tuebingen.de.
authors.forename: Thomas
authors.initials: T
authors.lastname: Euler
authors.affiliation: Institute for Ophthalmic Research, University of Tübingen; francois.paquet-durand@klinikum.uni-tuebingen.de.
authors.forename: Francois
authors.initials: F
authors.lastname: Paquet-Durand
mesh_terms: D000818:Animals; D001369:Axons / Q000737:chemistry / Q000378:metabolism*; D015374:Biosensing Techniques / Q000379:methods; D002118:Calcium / Q000032:analysis / Q000378:metabolism*; D020013:Calcium Signaling; D051379:Mice; D008822:Mice, Transgenic; D017729:Presynaptic Terminals / Q000737:chemistry / Q000378:metabolism*; D012160:Retina / Q000737:chemistry / Q000378:metabolism*; D017949:Retinal Cone Photoreceptor Cells / Q000737:chemistry / Q000378:metabolism*; D012162:Retinal Degeneration / Q000378:metabolism; D017948:Retinal Rod Photoreceptor Cells / Q000737:chemistry / Q000378:metabolism
chemical_list: D002118:Calcium