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: 582/1/95    most recent jphysiol.2007.127894v1 Services Email this article to a friend Similar articles in this journal 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 Google Scholar Google Scholar Articles by Osswald, I. K. Articles by Bowie, D. Search for Related Content PubMed PubMed Citation Articles by Osswald, I. K. Articles by Bowie, D. Related Collections Neuroscience Related Article

¹ Department of Pharmacology & Therapeutics, McGill University, Montreal, Quebec, Canada

Ca²+-permeable AMPA receptors (AMPARs) are expressed throughout the adult CNS but yet their role in development is poorly understood. In the developing retina, most investigations have focused on Ca²⁺ influx through NMDARs in promoting synapse maturation and not on AMPARs. However, NMDARs are absent from many retinal cells suggesting that other Ca²⁺-permeable glutamate receptors may be important to consider. Here we show that inhibitory horizontal and AII amacrine cells lack NMDARs but express Ca²⁺-permeable AMPARs. Before eye-opening, AMPARs were fully blocked by philanthotoxin (PhTX), a selective antagonist of Ca²⁺-permeable AMPARs. After eye-opening, however, a subpopulation of Ca²⁺-permeable AMPARs were unexpectedly PhTX resistant. Furthermore, Joro spider toxin (JSTX) and IEM-1460 also failed to antagonize, demonstrating that this novel pharmacology is shared by several AMPAR channel blockers. Interestingly, PhTX-insensitive AMPARs failed to express in retinae from dark-reared animals demonstrating that light entering the eye triggers their expression. Eye-opening coincides with the consolidation of inhibitory cell connections suggesting that the developmental switch to a Ca²⁺-permeable AMPAR with novel pharmacology may be critical to synapse maturation in the mammalian retina.

(Received 8 January 2007; accepted after revision 10 April 2007; first published online 12 April 2007)
Corresponding author D. Bowie: Department of Pharmacology & Therapeutics, McIntyre Medical Sciences Building, Room 1317, McGill University, 3655 Promenade Sir William Osler, Montreal, Québec, Canada H3A 1Y6. Email: derek.bowie{at}mcgill.ca

Related Article

A light switch controlling Ca²⁺-permeable AMPA receptors in the retina

Jeffrey S. Diamond
J. Physiol. 2007 582: 3. [Full Text] [PDF]

This article has been cited by other articles:

				A. T. E. Hartwick, C. M. Hamilton, and W. H. Baldridge Glutamatergic calcium dynamics and deregulation of rat retinal ganglion cells J. Physiol., July 15, 2008; 586(14): 3425 - 3446. [Abstract] [Full Text] [PDF]

				J. S. Diamond A light switch controlling Ca2+-permeable AMPA receptors in the retina J. Physiol., July 1, 2007; 582(1): 3 - 3. [Full Text] [PDF]