title: Ionotropic glutamate receptors of amacrine cells of the mouse retina.
abstract: The mammalian retina contains approximately 30 different morphological types of amacrine cells, receiving glutamatergic input from bipolar cells. In this study, we combined electrophysiological and pharmacological techniques in order to study the glutamate receptors expressed by different types of amacrine cells. Whole-cell currents were recorded from amacrine cells in vertical slices of the mouse retina. During the recordings the cells were filled with Lucifer Yellow/Neurobiotin allowing classification as wide-field or narrow-field amacrine cells. Amacrine cell recordings were also carried out in a transgenic mouse line whose glycinergic amacrine cells express enhanced green fluorescent protein (EGFP). Agonist-induced currents were elicited by exogenous application of NMDA, AMPA, and kainate (KA) while holding cells at -75 mV. Using a variety of specific agonists and antagonists (NBQX, AP5, cyclothiazide, GYKI 52466, GYKI 53655, SYM 2081) responses mediated by AMPA, KA, and NMDA receptors could be dissected. All cells (n = 300) showed prominent responses to non-NMDA agonists. Some cells expressed AMPA receptors exclusively and some cells expressed KA receptors exclusively. In the majority of cells both receptor types could be identified. NMDA receptors were observed in about 75% of the wide-field amacrine cells and in less than half of the narrow-field amacrine cells. Our results confirm that different amacrine cell types express distinct sets of ionotropic glutamate receptors, which may be critical in conferring their unique temporal responses to this diverse neuronal class.
authors.affiliation: Department of Neuroanatomy, Max-Planck-Institute for Brain Research, Frankfurt/Main, Germany.
authors.forename: Olivia N
authors.initials: ON
authors.lastname: Dumitrescu
authors.forename: Dario A
authors.initials: DA
authors.lastname: Protti
authors.forename: Sriparna
authors.initials: S
authors.lastname: Majumdar
authors.forename: Hanns Ulrich
authors.initials: HU
authors.lastname: Zeilhofer
authors.forename: Heinz
authors.initials: H
authors.lastname: Wässle
mesh_terms: D025042:Amacrine Cells / Q000187:drug effects / Q000378:metabolism* / Q000528:radiation effects; D000818:Animals; D001581:Benzothiadiazines / Q000494:pharmacology; D004307:Dose-Response Relationship, Radiation; D004347:Drug Interactions; D004558:Electric Stimulation / Q000379:methods; D018690:Excitatory Amino Acid Agonists / Q000494:pharmacology; D018691:Excitatory Amino Acid Antagonists / Q000494:pharmacology; D005455:Fluorescent Antibody Technique / Q000379:methods; D050487:Glycine Plasma Membrane Transport Proteins / Q000378:metabolism; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000378:metabolism; D066298:In Vitro Techniques; D008564:Membrane Potentials / Q000187:drug effects / Q000502:physiology / Q000528:radiation effects; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic / Q000235:genetics / Q000378:metabolism; D018408:Patch-Clamp Techniques / Q000379:methods; D017470:Receptors, Glutamate / Q000145:classification / Q000502:physiology*; D012160:Retina / Q000166:cytology* / Q000187:drug effects; D005680:gamma-Aminobutyric Acid / Q000378:metabolism
chemical_list: D001581:Benzothiadiazines; D018690:Excitatory Amino Acid Agonists; D018691:Excitatory Amino Acid Antagonists; D050487:Glycine Plasma Membrane Transport Proteins; D017470:Receptors, Glutamate; D049452:Green Fluorescent Proteins; D005680:gamma-Aminobutyric Acid; C004639:cyclothiazide