title: Electroretinographic assessment of rod- and cone-mediated bipolar cell pathways using flicker stimuli in mice.
abstract: Mouse full-field electroretinograms (ERGs) are dominated by responses of photoreceptors and depolarizing (ON-) bipolar cells, but not much of hyperpolarizing (OFF-) bipolar cells under conventional recording conditions. Here we investigate a novel ERG protocol in mice for functional assessment of the major ON- and OFF-bipolar cell pathways using flicker stimuli for a high luminance with varying frequency up to 30 Hz. Wild-type (WT) and functionally specific transgenic mice (Cnga3(-/-), no cone photoreceptor function; rho(-/-), no rod photoreceptor function; mGluR6(-/-), no ON-bipolar cell function) were examined. The Cnga3(-/-) flicker ERG was similar to the WT flicker ERG at very low stimulus frequencies, whereas ERGs were comparable between WT and rho(-/-) mice at 5 Hz and above. Between 5 and 15 Hz, ERGs in mGluR6(-/-) mice differed in configuration and amplitude from those in WT and rho(-/-) mice; in contrast, response amplitudes above 15 Hz were comparable among WT, rho(-/-) and mGluR6(-/-) mice. In summary, we found three frequency ranges with these conditions that are dominated by activity in the rod pathways (below 5 Hz), cone ON-pathway (between 5 and 15 Hz), and cone OFF-pathway (above 15 Hz) that enables a quick overview of the functionality of the major bipolar cell pathways.
authors.affiliation: Division of Ocular Neurodegeneration, Institute for Ophthalmic Research, Centre for Ophthalmology, Eberhard Karls University, Schleichstr. 4/3, D-72076 Tübingen, Germany.
authors.forename: Naoyuki
authors.initials: N
authors.lastname: Tanimoto
authors.affiliation: Division of Ocular Neurodegeneration, Institute for Ophthalmic Research, Centre for Ophthalmology, Eberhard Karls University, Schleichstr. 4/3, D-72076 Tübingen, Germany.
authors.forename: Vithiyanjali
authors.initials: V
authors.lastname: Sothilingam
authors.affiliation: Department of Ophthalmology, Mie University Graduate School of Medicine, 2-175 Edobashi, Tsu, Mie 514-8507, Japan.
authors.forename: Mineo
authors.initials: M
authors.lastname: Kondo
authors.affiliation: Center for Integrated Protein Science Munich, CIPSM and Department of Pharmacy - Center for Drug Research, Ludwig-Maximilians-Universität München, Butenandtstr. 5-13, D-81377 München, Germany.
authors.forename: Martin
authors.initials: M
authors.lastname: Biel
authors.affiliation: The Ocular Genetics Unit, Smurfit Institute of Genetics, Trinity College Dublin, Dublin 2, Ireland.
authors.forename: Peter
authors.initials: P
authors.lastname: Humphries
authors.affiliation: Division of Ocular Neurodegeneration, Institute for Ophthalmic Research, Centre for Ophthalmology, Eberhard Karls University, Schleichstr. 4/3, D-72076 Tübingen, Germany.
authors.forename: Mathias W
authors.initials: MW
authors.lastname: Seeliger
mesh_terms: D000818:Animals; D004596:Electroretinography; D005074:Evoked Potentials, Visual; D051379:Mice; D018345:Mice, Knockout; D010775:Photic Stimulation; D017949:Retinal Cone Photoreceptor Cells / Q000378:metabolism*; D017948:Retinal Rod Photoreceptor Cells / Q000378:metabolism*; D015398:Signal Transduction