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photoreceptors, physiology, signal transduction, retina, vision, neurodegeneration

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McMillan Bldg, Room 625



Research Abstract

We derive most of our information about the world through our visual system by means of rod and cone photoreceptors. The human retina has one type of rod for dim light vision, and three types of cone cells that allow color discrimination. Despite the similarities in their morphology and mechanism of light detection, rods and cones have distinct functional properties. Rods are extremely sensitive (they can detect a single photon of light!) and thus are perfectly suited for dim light conditions. They saturate in moderate light, however, and are not able to respond to light through most of the day. Cones, on the other hand, are 30-100 times less sensitive than rods and do not respond to light in dim light conditions (this is why we don’t see colors at night). However, cones are capable of adapting to an extremely wide range of light conditions, rendering them perfectly suited as our daytime photoreceptors. Our lab is interested in the mechanisms that determine the functional properties of mammalian rod and cone photoreceptors. We use a battery of tools, from single-cell and isolated retina recordings, to live electroretinogram and behavior experiments with wild type and genetically modified mice. While the emphasis of our studies is on our daytime photoreceptors, the cones, we are also investigating some aspects of rod phototransduction.

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Vladimir J. Kefalov

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Physiology of photoreceptors

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Date Last Updated

11/10/2011 11:03 AM


Sakurai K, Chen J, Kefalov VJ.  Role of guanylyl cyclase modulation in mouse cone phototransduction. J Neurosci. 2011 31(22): 7991-8000. MCID: PMC3124626
Kolesnikov AV, Tang PH, Parker RO, Crouch RK, Kefalov VJ.  The mammalian cone visual cycle promotes rapid M/L-cone pigment regeneration independently of the interphotoreceptor retinoid-binding protein. J Neurosci. 2011 31(21): 7900-9. PMCID: PMC3108150
Kolesnikov AV, Fan J, Crouch RK, Kefalov VJ.  Age-related deterioration of rod vision in mice. J Neurosci. 2010 30(33): 11222-31. PMCID: PMC2928554
Wang JS, Kefalov VJ.  An alternative pathway mediates the mouse and human cone visual cycle. Curr Biol. 2009 19(19): 1665-9. PMCID: PMC2762012
Wang JS, Estevez ME, Cornwall MC, Kefalov VJ.  Intra-retinal visual cycle required for rapid and complete cone dark adaptation. Nat Neurosci. 2009 12(3): 295-302. PMCID: PMC2707787

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Thumbnail_Image_Url Photos Thumbnail/Kefalov_V.jpg

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Research Image Description

Acute treatment with the gliotoxin L-α-AAA kills most Müller glial cells in the mouse retina as demonstrated by Müller cell-specific immunolabeling. Missing Müller cell nuclei in right panel are indicated by arrowheads. Removal of Müller glia blocks the ability of the retina to promote cone pigment regeneration demonstrating the critical role these cells play in the recycling of chromophore within the neural retina.

Research Image Url Research Images/Vladimir_Kefalov_5993.jpg

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Created at 11/10/2011 11:03 AM by DBBS_SP_SAPP
Last modified at 11/10/2011 1:01 PM by Kathryn Ruzicka