HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) All Versions of this Article: 94/3/1770    most recent 00279.2005v1 Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in ISI Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via ISI Web of Science (5) Citing Articles via Google Scholar Google Scholar Articles by Petit-Jacques, J. Articles by Bloomfield, S. Search for Related Content PubMed PubMed Citation Articles by Petit-Jacques, J. Articles by Bloomfield, S.

Spontaneous Oscillatory Activity of Starburst Amacrine Cells in the Mouse Retina

¹Departments of Ophthalmology, ²Physiology and Neuroscience, and ³Biochemistry, New York University School of Medicine, New York, New York

Submitted 15 March 2005; accepted in final form 18 May 2005

Using patch-clamp techniques, we investigated the characteristics of the spontaneous oscillatory activity displayed by starburst amacrine cells in the mouse retina. At a holding potential of –70 mV, oscillations appeared as spontaneous, rhythmic inward currents with a frequency of 3.5 Hz and an average maximal amplitude of 120 pA. Application of TEA, a potassium channel blocker, increased the amplitude of oscillatory currents by >70% but reduced their frequency by 17%. The TEA effects did not appear to result from direct actions on starburst cells, but rather a modulation of their synaptic inputs. Oscillatory currents were inhibited by 6-cyano-7-nitroquinoxalene-2,3-dione (CNQX), an antagonist of AMPA/kainate receptors, indicating that they were dependent on a periodic glutamatergic input likely from presynaptic bipolar cells. The oscillations were also inhibited by the calcium channel blockers cadmium and nifedipine, suggesting that the glutamate release was calcium dependent. Application of AP4, an agonist of mGluR6 receptors on on-center bipolar cells, blocked the oscillatory currents in starburst cells. However, application of TEA overcame the AP4 blockade, suggesting that the periodic glutamate release from bipolar cells is intrinsic to the inner plexiform layer in that, under experimental conditions, it can occur independent of photoreceptor input. The GABA receptor antagonists picrotoxin and bicuculline enhanced the amplitude of oscillations in starburst cells prestimulated with TEA. Our results suggest that this enhancement was due to a reduction of a GABAergic feedback inhibition from amacrine cells to bipolar cells and the resultant increased glutamate release. Finally, we found that some ganglion cells and other types of amacrine cell also displayed rhythmic activity, suggesting that oscillatory behavior is expressed by a number of inner retinal neurons.

This article has been cited by other articles:

				J. Petit-Jacques and S. A. Bloomfield Synaptic Regulation of the Light-Dependent Oscillatory Currents in Starburst Amacrine Cells of the Mouse Retina J Neurophysiol, August 1, 2008; 100(2): 993 - 1006. [Abstract] [Full Text] [PDF]

				J. M. Ackert, S. H. Wu, J. C. Lee, J. Abrams, E. H. Hu, I. Perlman, and S. A. Bloomfield Light-induced changes in spike synchronization between coupled ON direction selective ganglion cells in the mammalian retina. J. Neurosci., April 19, 2006; 26(16): 4206 - 4215. [Abstract] [Full Text] [PDF]