title: Rod electrical coupling is controlled by a circadian clock and dopamine in mouse retina.
abstract: Rod single-photon responses are critical for vision in dim light. Electrical coupling via gap junction channels shapes the light response properties of vertebrate photoreceptors, but the regulation of rod coupling and its impact on the single-photon response have remained unclear. To directly address these questions, we developed a perforated patch-clamp recording technique and recorded from single rod inner segments in isolated intact neural mouse retinae, maintained by superfusion. Experiments were conducted at different times of the day or under constant environmental conditions, at different times across the circadian cycle. We show that rod electrical coupling is regulated by a circadian clock and dopamine, so that coupling is weak during the day and strong at night. Altogether, patch-clamp recordings of single-photon responses in mouse rods, tracer coupling, receptive field measurements and pharmacological manipulations of gap junction and dopamine receptor activity provide compelling evidence that rod coupling is modulated in a circadian manner. These data are consistent with computer modelling. At night, single-photon responses are smaller due to coupling, but the signal-to-noise ratio for a dim (multiphoton) light response is increased at night because of signal averaging between coupled rods.
authors.affiliation: Ruiz Department of Ophthalmology and Visual Science, Medical School, The University of Texas Health Science Centre at Houston, 6431 Fannin Street, Suite MSB 7.024, Houston, TX, 77030, USA.
authors.forename: Nan Ge
authors.initials: NG
authors.lastname: Jin
authors.forename: Alice Z
authors.initials: AZ
authors.lastname: Chuang
authors.forename: Philippe J
authors.initials: PJ
authors.lastname: Masson
authors.forename: Christophe P
authors.initials: CP
authors.lastname: Ribelayga
mesh_terms: D000818:Animals; D057906:Circadian Clocks / Q000502:physiology*; D004298:Dopamine / Q000502:physiology*; D066298:In Vitro Techniques; D008027:Light; D008808:Mice, Inbred CBA; D018408:Patch-Clamp Techniques; D017785:Photons; D012160:Retina / Q000502:physiology*; D017948:Retinal Rod Photoreceptor Cells / Q000502:physiology*; D059629:Signal-To-Noise Ratio
chemical_list: D004298:Dopamine