title: Directional excitatory input to direction-selective ganglion cells in the rabbit retina.
abstract: Directional responses in retinal ganglion cells are generated in large part by direction-selective release of γ-aminobutyric acid from starburst amacrine cells onto direction-selective ganglion cells (DSGCs). The excitatory inputs to DSGCs are also widely reported to be direction-selective, however, recent evidence suggests that glutamate release from bipolar cells is not directional, and directional excitation seen in patch-clamp analyses may be an artifact resulting from incomplete voltage control. Here, we test this voltage-clamp-artifact hypothesis in recordings from 62 ON-OFF DSGCs in the rabbit retina. The strength of the directional excitatory signal varies considerably across the sample of cells, but is not correlated with the strength of directional inhibition, as required for a voltage-clamp artifact. These results implicate additional mechanisms in generating directional excitatory inputs to DSGCs.
authors.affiliation: Department of Ophthalmology, Casey Eye Institute, Oregon Health & Science University, Portland, Oregon.
authors.forename: Kumiko A
authors.initials: KA
authors.lastname: Percival
authors.affiliation: Department of Ophthalmology, Casey Eye Institute, Oregon Health & Science University, Portland, Oregon.
authors.forename: Sowmya
authors.initials: S
authors.lastname: Venkataramani
authors.affiliation: Department of Neuroscience, University of Pennsylvania, Philadelphia, Pennsylvania.
authors.forename: Robert G
authors.initials: RG
authors.lastname: Smith
authors.affiliation: Department of Ophthalmology, Casey Eye Institute, Oregon Health & Science University, Portland, Oregon.
authors.forename: W Rowland
authors.identifier: 0000-0002-6806-3249
authors.initials: WR
authors.lastname: Taylor
mesh_terms: D000818:Animals; D008564:Membrane Potentials / Q000502:physiology*; D018408:Patch-Clamp Techniques; D011817:Rabbits; D012165:Retinal Ganglion Cells / Q000502:physiology*; D009435:Synaptic Transmission / Q000502:physiology*
keywords: RRID:SCR_000325; amacrine cells; direction selective; excitation; inhibition; rabbit; retinal ganglion cell; synaptic transmission; voltage clamp