Noga Vardi, Ph.D

faculty photo
Adjunct Professor of Neuroscience
Department: Neuroscience

Contact information
123A Anatomy-Chemistry Building
Department of Neuroscience
Perelman School of Medicine
University of Pennsylvania
Philadelphia, PA 19104-6058
Office: 215-898-4520
Fax: 215-898-6228
Education:
B.Sc (Biology)
Hebrew University, Jerusalem, 1974.
(Courses toward M.A in Neuroscience)
Hebrew University, Jerusalem, 1975.
Ph.D. (Maj. Neurobiology and Behavior, Min. Elec. Eng)
Cornell University, 1981.
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Description of Research Expertise

RESEARCH INTERESTS
Retinal processing with focus on chemical architecture and principles of signal processing.

RESEARCH TECHNIQUES
Electrophysiology; immunocytochemistry; electroretinogram; dye injection; electron microscopy; molecular biology; yeast two hybrid systems; computer simulation; live two photon imaging.

RESEARCH SUMMARY
General Description: General Description: The retina provides an excellent model system for signal processing because the input (visual image) is well defined, the output (ganglion cell responses) has been thoroughly studied, and circuits of parallel pathways from photoreceptor to ganglion cells were described better than any other neural system. To reliably transfer the signal from photoreceptor to ganglion cells through these pathways under a large range of luminances the retina employs gain control and noise removal mechanisms. Gain is adjusted by GABAergic and glycinergic feedback circuits in the outer and inner plexiform layers. These circuits tune photoreceptor, bipolar and ganglion cells' responses by averaging and feeding back ambient light information. A major focus of the lab is the pathway of the ON bipolar cells and their signaling cascade. The ON bipolar cells express the metabotropic glutamate receptor mGluR6. This receptor activates Go, and this eventually closes the nonspecific TRPM1 cation channel. We are studying the events that occur downstream of Go and how they are modulated. Whether Go activates directly the channel, or through a second messenger is important because the manner of activation determines the gain and the adaptation of these cells. In particular, both mGluR6 and Go are present in both rod and cone bipolar cells, but the two classes have different function (slow for night vision vs. fast for day vision), and one expects the cascade to differ in order to match and optimize the function. In addition, we study how the whole complex of the cascade is trafficked to the dendritic tip, and how a lack of a certain element destabilizes the complex and the synapse. Knowledge of this cascade is essential for understanding and treating night blindness. A second project concerns cone bipolar cell types; there exist about 5 types that are thought to conduct different temporal bandwidth. Nothing is known about their precise light properties and how they achieve their differences. We study this by calcium imaging of ON bipolar cells. Such understanding will shed light on day light vision. Other projects involve cone vision and G-protein signaling. I am recently engaged in applying the knowledge we acquired to therapeutic methods for structural and functional protection of retinal circuits.

Selected Publications

Ramakrishnan Hariharasubramanian, Dhingra Anuradha, Tummala Shanti R, Fina Marie E, Li Jian J, Lyubarsky Arkady, Vardi Noga: Differential Function of Gγ13 in Rod Bipolar and ON Cone Bipolar Cells. The Journal of physiology 593(7): 1531-50, Nov 2014.

Dhingra A, Tummala SR, Lyubarsky L, and Vardi N: PDE9A is expressed in the inner retina and contributes to the normal shape of the photopic ERG waveform. Frontiers in Molecular Neuroscience 7: 60, June 2014.

Devi Sulochana, Markandeya Yogananda, Maddodi Nityanand, Dhingra Anuradha, Vardi Noga, Balijepalli Ravi C, Setaluri Vijayasaradhi: Metabotropic glutamate receptor 6 signaling enhances TRPM1 calcium channel function and increases melanin content in human melanocytes. Pigment cell & melanoma research 26(3): 348-56, May 2013.

Nikonov Sergei S, Lyubarsky Arkady, Fina Marie E, Nikonova Elena S, Sengupta Abhishek, Chinniah Chidambaram, Ding Xi-Qin, Smith Robert G, Pugh Edward N, Vardi Noga, Dhingra Anuradha: Cones respond to light in the absence of transducin β subunit. The Journal of neuroscience : the official journal of the Society for Neuroscience 33(12): 5182-94, Mar 2013.

Sulaiman Pyroja, Xu Ying, Fina Marie E, Tummala Shanti R, Ramakrishnan Hariharasubramanian, Dhingra Anuradha, Vardi Noga: Kir2.4 surface expression and basal current are affected by heterotrimeric G-proteins. The Journal of biological chemistry 288(10): 7420-9, Mar 2013.

Dhingra Anuradha, Ramakrishnan Hariharasubramanian, Neinstein Adam, Fina Marie E, Xu Ying, Li Jian, Chung Daniel C, Lyubarsky Arkady, Vardi Noga: Gβ3 is required for normal light ON responses and synaptic maintenance. The Journal of neuroscience : the official journal of the Society for Neuroscience 32(33): 11343-55, Aug 2012.

Xu Y, Dhingra A, Fina ME, Koike C, Furukawa T, Vardi N.: mGluR6 deletion renders the TRPM1 channel in retina inactive. J Neurophysiol. 107(3): 948-57, Feb 2012.

Xu Ying, Sulaiman Pyroja, Feddersen Rod M, Liu Jian, Smith Robert G, Vardi Noga: Retinal ON bipolar cells express a new PCP2 splice variant that accelerates the light response. The Journal of neuroscience : the official journal of the Society for Neuroscience 28(36): 8873-84, Sep 2008.

Zhang Ling-Li, Fina Marie E, Vardi Noga: Regulation of KCC2 and NKCC during development: membrane insertion and differences between cell types. The Journal of comparative neurology 499(1): 132-43, Nov 2006.

Dhingra Anuradha, Jiang Meisheng, Wang Tian-Li, Lyubarsky Arkady, Savchenko Andrey, Bar-Yehuda Tehilla, Sterling Peter, Birnbaumer Lutz, Vardi Noga: Light response of retinal ON bipolar cells requires a specific splice variant of Galpha(o). The Journal of neuroscience : the official journal of the Society for Neuroscience 22(12): 4878-84, Jun 2002.

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Last updated: 12/01/2016
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