The Journal of Neuroscience, July 22, 2009, 29(29):9186-9196; doi:10.1523/JNEUROSCI.0184-09.2009
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Development/Plasticity/Repair
Ectopic Expression of Multiple Microbial Rhodopsins Restores ON and OFF Light Responses in Retinas with Photoreceptor Degeneration
Yi Zhang,
Elena Ivanova,
Anding Bi, and
Zhuo-Hua Pan
Department of Anatomy and Cell Biology, Wayne State University School of Medicine, Detroit, Michigan 48201
Correspondence should be addressed to Dr. Zhuo-Hua Pan, Department of Anatomy and Cell Biology, Wayne State University School of Medicine, 540 East Canfield Avenue, Detroit, MI 48201. Email: zhpan{at}med.wayne.edu
By expressing channelrhodopsin-2 (ChR2) in inner retinal neurons, previous studies have demonstrated restoration of ON responses in the retina after the death of rod and cone photoreceptors. In this study, we report that the expression of halorhodopsin (HaloR), a light-driven chloride pump, can effectively restore OFF responses in inner retinal neurons of mice with retinal degeneration. We show that HaloR-expressing retinal ganglion cells respond to light with rapid hyperpolarization and suppression of spike activity. After termination of the light stimulus, their membrane potential exhibits a rapid rebound overshoot with robust sustained or transient spike firing. Furthermore, we show that coexpression of ChR2/HaloR in retinal ganglion cells can produce ON, OFF, and even ON–OFF responses, depending on the wavelength of the light stimulus. Our results suggest that the expression of multiple microbial rhodopsins such as ChR2 and HaloR is a possible strategy to restore both ON and OFF light responses in the retina after the death of rod and cone photoreceptors.
Received Jan. 12, 2009;
revised June 10, 2009;
accepted June 16, 2009.
Correspondence should be addressed to Dr. Zhuo-Hua Pan, Department of Anatomy and Cell Biology, Wayne State University School of Medicine, 540 East Canfield Avenue, Detroit, MI 48201. Email: zhpan{at}med.wayne.edu
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