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This Article Full Text Full Text (PDF) All Versions of this Article: 554/3/649    most recent jphysiol.2003.056309v1 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 Google Scholar Google Scholar Articles by Han, Y. Articles by Slaughter, M. M. Search for Related Content PubMed PubMed Citation Articles by Han, Y. Articles by Slaughter, M. M.

Departments of Physiology & Biophysics and Ophthalmology, School of Medicine, State University of New York at Buffalo, 124 Sherman Hall, Buffalo, NY 14214, USA

Retinal ganglion cells exhibit fast and slow inhibitory synaptic glycine currents that can be selectively inhibited by strychnine and 5,7-dichlorokynurenic acid (DCKA), respectively. In this study we examined whether strychnine and DCKA selectivity correlated with the subunit composition of the glycine receptor. Homomeric 1, 2 or 2* glycine subunits were in vitro expressed in human embryonic kidney cells (HEK 293). In cells expressing the 1 subunit, responses to 200 µM glycine were blocked by 1 µM strychnine but not by 500 µM DCKA. In cells expressing the 2 subunit, both 1 µM strychnine and 500 µM DCKA were effective antagonists of 200 µM glycine. In cells expressing 2* subunits, which are much less glycine-sensitive, 10 mM glycine was inhibited by 500 µM DCKA but not by 1 µM strychnine. A single amino acid mutation in the 1 subunit (R196G), converted this subunit from DCKA-insensitive to DCKA-sensitive. In conclusion, the comparative effectiveness of strychnine and DCKA can be used to distinguish between the 1, 2 and 2* receptor responses. Furthermore, a single amino acid near the glycine receptor's putative agonist binding site may account for differences in DCKA sensitivity amongst the subunits.

(Received 7 October 2003; accepted after revision 27 November 2003; first published online 28 November 2003)
Corresponding author M. M. Slaughter: University at Buffalo School of Medicine, Department of Physiology & Biophysics, 124 Sherman Hall, 3435 Main Street, Buffalo, NY 14214, USA. Email: mslaught{at}buffalo.edu