JN AJP: Cell Physiology
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH
 QUICK SEARCH:   [advanced]


     


J Neurophysiol (May 21, 2008). doi:10.1152/jn.01399.2007
This Article
Right arrow Full Text (PDF)
Right arrow All Versions of this Article:
100/2/993    most recent
01399.2007v1
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Citing Articles
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Petit-Jacques, J.
Right arrow Articles by Bloomfield, S. A
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Petit-Jacques, J.
Right arrow Articles by Bloomfield, S. A
Submitted on December 27, 2007
Accepted on May 14, 2008

Synaptic regulation of the light-dependent oscillatory currents in starburst amacrine cells of the mouse retina

Jerome Petit-Jacques1* and Stewart A Bloomfield1

1 Ophthalmology, Physiology and Neuroscience, New York University School of Medicine, New York, New York, United States

* To whom correspondence should be addressed. E-mail: jpjalpha{at}yahoo.com.

Responses of on-center starburst amacrine cells to steady light stimuli were recorded in the dark adapted mouse retina. The response to spots of dim white light appear to show two components, an initial peak that correspond to the onset of the light stimulus, and a series of oscillations that ride on top of the initial peak relaxation. The frequency of oscillations during light stimulation was three time higher than the frequency of spontaneous oscillations recorded in the dark. The light-evoked responses in starburst cells were exclusively dependent on the release of glutamate likely from presynaptic bipolar axon terminals and the binding of glutamate to AMPA/kainate receptors because they were blocked by CNQX. The synaptic pathway responsible for the light responses was blocked by AP4, an agonist of metabotropic glutamate receptors that hyperpolarize on-center bipolar cells upon activation. Light responses were inhibited by the calcium channel blockers cadmium ions and nifedipine suggesting that the release of glutamate was calcium dependent. The oscillatory component of the response was specifically inhibited by blocking the glutamate transporter with TBOA, suggesting that glutamate reuptake is necessary for the oscillatory release. GABAergic antagonists bicuculline, SR 95531 and picrotoxin increased the amplitude of the initial peak while they inhibit the frequency of oscillations. TTX had a similar effect. Strychnine, the blocker of glycine receptors did not affect the initial peak but strongly decreased the oscillations frequency. These inhibitory inputs onto the bipolar axon terminals shape and synchronize the oscillatory component. Keywords: amacrine cells, oscillations, retina, glutamate







HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH
Visit Other APS Journals Online
Copyright © 2008 by the The American Physiological Society.