Document Detail


Light-evoked oscillatory discharges in retinal ganglion cells are generated by rhythmic synaptic inputs.
MedLine Citation:
PMID:  15277593     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
In the visual system, optimal light stimulation sometimes generates gamma-range (ca. 20 approximately 80 Hz) synchronous oscillatory spike discharges. This phenomenon is assumed to be related to perceptual integration. Applying a planar multi-electrode array to the isolated frog retina, Ishikane et al. demonstrated that dimming detectors, off-sustained type ganglion cells, generate synchronous oscillatory spike discharges in response to diffuse dimming illumination. In the present study, applying the whole cell current-clamp technique to the isolated frog retina, we examined how light-evoked oscillatory spike discharges were generated in dimming detectors. Light-evoked oscillatory ( approximately 30 Hz) spike discharges were triggered by rhythmic ( approximately 30 Hz) fluctuations superimposed on a depolarizing plateau potential. When a suprathreshold steady depolarizing current was injected into a dimming detector, only a few spikes were evoked at the stimulus onset. However, repetitive spikes were triggered by a gamma-range sinusoidal current superimposed on the steady depolarizing current. Thus the light-evoked rhythmic fluctuations are likely to be generated presynaptically. The light-evoked rhythmic fluctuations were suppressed not by intracellular application of N-(2,6-dimethyl-phenylcarbamoylmethyl)triethylammonium bromide (QX-314), a Na(+) channel blocker, to the whole cell clamped dimming detector but by bath-application of tetrodotoxin to the retina. The light-evoked rhythmic fluctuations were suppressed by a GABA(A) receptor antagonist but potentiated by a GABA(C) receptor antagonist, whereas these fluctuations were little affected by a glycine receptor antagonist. Because amacrine cells are spiking neurons and because GABA is one of the main transmitters released from amacrine cells, amacrine cells may participate in generating rhythmically fluctuated synaptic input to dimming detectors.
Authors:
Itaru Arai; Yoshiyuki Yamada; Tomomitsu Asaka; Masao Tachibana
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Publication Detail:
Type:  In Vitro; Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Journal of neurophysiology     Volume:  92     ISSN:  0022-3077     ISO Abbreviation:  J. Neurophysiol.     Publication Date:  2004 Aug 
Date Detail:
Created Date:  2004-07-27     Completed Date:  2004-09-21     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  0375404     Medline TA:  J Neurophysiol     Country:  United States    
Other Details:
Languages:  eng     Pagination:  715-25     Citation Subset:  IM    
Affiliation:
Dept. of Psychology, Graduate School of Humanities and Sociology, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.
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MeSH Terms
Descriptor/Qualifier:
Animals
Electric Stimulation
Light*
Membrane Potentials
Neural Inhibition / physiology
Patch-Clamp Techniques
Periodicity*
Photic Stimulation / methods
Rana catesbeiana
Rats
Retinal Ganglion Cells / cytology,  metabolism,  physiology*,  radiation effects*
Sodium Channels / physiology
Synapses / physiology*
Synaptic Transmission / physiology
Chemical
Reg. No./Substance:
0/Sodium Channels

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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