title: Modulation of rod photoreceptor output by HCN1 channels is essential for regular mesopic cone vision.
abstract: Retinal photoreceptors permit visual perception over a wide range of lighting conditions. Rods work best in dim, and cones in bright environments, with considerable functional overlap at intermediate (mesopic) light levels. At many sites in the outer and inner retina where rod and cone signals interact, gap junctions, particularly those containing Connexin36, have been identified. However, little is known about the dynamic processes associated with the convergence of rod and cone system signals into ON- and OFF-pathways. Here we show that proper cone vision under mesopic conditions requires rapid adaptational feedback modulation of rod output via hyperpolarization-activated and cyclic nucleotide-gated channels 1. When these channels are absent, sustained rod responses following bright light exposure saturate the retinal network, resulting in a loss of downstream cone signalling. By specific genetic and pharmacological ablation of key signal processing components, regular cone signalling can be restored, thereby identifying the sites involved in functional rod-cone interactions.
authors: Division of Ocular Neurodegeneration, Institute for Ophthalmic Research, Centre for Ophthalmology, Eberhard Karls University of Tübingen, Schleichstr. 4/3, D-72076 Tübingen, Germany. see@uni-tuebingen.de
authors: Mathias W
authors: MW
authors: Seeliger
authors: Arne
authors: A
authors: Brombas
authors: Reto
authors: R
authors: Weiler
authors: Peter
authors: P
authors: Humphries
authors: Gabriel
authors: G
authors: Knop
authors: Naoyuki
authors: N
authors: Tanimoto
authors: Frank
authors: F
authors: Müller
mesh_terms: D000818:Animals; D054815:Cyclic Nucleotide-Gated Cation Channels / Q000235:genetics / Q000378:metabolism*; D004594:Electrophysiology; D004596:Electroretinography; D064428:Hyperpolarization-Activated Cyclic Nucleotide-Gated Channels; D066298:In Vitro Techniques; D051379:Mice; D018345:Mice, Knockout; D015221:Potassium Channels / Q000235:genetics / Q000378:metabolism*; D012160:Retina / Q000378:metabolism / Q000502:physiology; D017949:Retinal Cone Photoreceptor Cells / Q000378:metabolism*; D017948:Retinal Rod Photoreceptor Cells / Q000378:metabolism*; D055258:Rod-Cone Interaction / Q000235:genetics / Q000502:physiology*; D015398:Signal Transduction / Q000235:genetics / Q000502:physiology; D014785:Vision, Ocular / Q000235:genetics / Q000502:physiology
chemical_list: D054815:Cyclic Nucleotide-Gated Cation Channels; C578666:Hcn1 protein, mouse; D064428:Hyperpolarization-Activated Cyclic Nucleotide-Gated Channels; D015221:Potassium Channels