Document Detail


Phosducin regulates transmission at the photoreceptor-to-ON-bipolar cell synapse.
MedLine Citation:
PMID:  20203183     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
The rate of synaptic transmission between photoreceptors and bipolar cells has been long known to depend on conditions of ambient illumination. However, the molecular mechanisms that mediate and regulate transmission at this ribbon synapse are poorly understood. We conducted electroretinographic recordings from dark- and light-adapted mice lacking the abundant photoreceptor-specific protein phosducin and found that the ON-bipolar cell responses in these animals have a reduced light sensitivity in the dark-adapted state. Additional desensitization of their responses, normally caused by steady background illumination, was also diminished compared with wild-type animals. This effect was observed in both rod- and cone-driven pathways, with the latter affected to a larger degree. The underlying mechanism is likely to be photoreceptor specific because phosducin is not expressed in other retina neurons and transgenic expression of phosducin in rods of phosducin knock-out mice rescued the rod-specific phenotype. The underlying mechanism functions downstream from the phototransduction cascade, as evident from the sensitivity of phototransduction in phosducin knock-out rods being affected to a much lesser degree than b-wave responses. These data indicate that a major regulatory component responsible for setting the sensitivity of signal transmission between photoreceptors and ON-bipolar cells is confined to photoreceptors and that phosducin participates in the underlying molecular mechanism.
Authors:
Rolf Herrmann; Ekaterina S Lobanova; Timothy Hammond; Christopher Kessler; Marie E Burns; Laura J Frishman; Vadim Y Arshavsky
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Publication Detail:
Type:  Journal Article; Research Support, N.I.H., Extramural; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  The Journal of neuroscience : the official journal of the Society for Neuroscience     Volume:  30     ISSN:  1529-2401     ISO Abbreviation:  J. Neurosci.     Publication Date:  2010 Mar 
Date Detail:
Created Date:  2010-03-05     Completed Date:  2010-05-05     Revised Date:  2011-09-26    
Medline Journal Info:
Nlm Unique ID:  8102140     Medline TA:  J Neurosci     Country:  United States    
Other Details:
Languages:  eng     Pagination:  3239-53     Citation Subset:  IM    
Affiliation:
Albert Eye Research Institute, Duke University, Durham, North Carolina 27710, USA.
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MeSH Terms
Descriptor/Qualifier:
Adaptation, Ocular / genetics,  radiation effects
Animals
Dark Adaptation / genetics,  radiation effects
Electroretinography
Eye Proteins / genetics*,  metabolism
GTP-Binding Protein Regulators / genetics*,  metabolism
Gene Expression Regulation / physiology
Light
Mice
Mice, Knockout
Mice, Transgenic
Phosphoproteins / genetics*,  metabolism
Photic Stimulation
Photoreceptor Cells, Vertebrate / cytology,  metabolism*,  radiation effects
Retinal Bipolar Cells / cytology,  metabolism*,  radiation effects
Synapses / genetics,  metabolism,  ultrastructure
Synaptic Transmission / genetics*,  radiation effects
Vision, Ocular / genetics*,  radiation effects
Visual Pathways / cytology,  metabolism*,  radiation effects
Grant Support
ID/Acronym/Agency:
EY06671/EY/NEI NIH HHS; EY10336/EY/NEI NIH HHS; EY14047/EY/NEI NIH HHS; EY5722/EY/NEI NIH HHS; P30 EY005722-25/EY/NEI NIH HHS; P30 EY007551-24/EY/NEI NIH HHS; R01 EY006671-16/EY/NEI NIH HHS; R01 EY010336-20/EY/NEI NIH HHS; R01 EY014047-09/EY/NEI NIH HHS
Chemical
Reg. No./Substance:
0/Eye Proteins; 0/GTP-Binding Protein Regulators; 0/Phosphoproteins; 0/phosducin

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